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linux/arch/tile/kernel/unaligned.c

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/*
* Copyright 2013 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* A code-rewriter that handles unaligned exception.
*/
#include <linux/smp.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/thread_info.h>
#include <linux/uaccess.h>
#include <linux/mman.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/prctl.h>
#include <asm/cacheflush.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
#include <arch/abi.h>
#include <arch/spr_def.h>
#include <arch/opcode.h>
/*
* This file handles unaligned exception for tile-Gx. The tilepro's unaligned
* exception is supported out of single_step.c
*/
int unaligned_printk;
static int __init setup_unaligned_printk(char *str)
{
long val;
if (kstrtol(str, 0, &val) != 0)
return 0;
unaligned_printk = val;
pr_info("Printk for each unaligned data accesses is %s\n",
unaligned_printk ? "enabled" : "disabled");
return 1;
}
__setup("unaligned_printk=", setup_unaligned_printk);
unsigned int unaligned_fixup_count;
#ifdef __tilegx__
/*
* Unalign data jit fixup code fragement. Reserved space is 128 bytes.
* The 1st 64-bit word saves fault PC address, 2nd word is the fault
* instruction bundle followed by 14 JIT bundles.
*/
struct unaligned_jit_fragment {
unsigned long pc;
tilegx_bundle_bits bundle;
tilegx_bundle_bits insn[14];
};
/*
* Check if a nop or fnop at bundle's pipeline X0.
*/
static bool is_bundle_x0_nop(tilegx_bundle_bits bundle)
{
return (((get_UnaryOpcodeExtension_X0(bundle) ==
NOP_UNARY_OPCODE_X0) &&
(get_RRROpcodeExtension_X0(bundle) ==
UNARY_RRR_0_OPCODE_X0) &&
(get_Opcode_X0(bundle) ==
RRR_0_OPCODE_X0)) ||
((get_UnaryOpcodeExtension_X0(bundle) ==
FNOP_UNARY_OPCODE_X0) &&
(get_RRROpcodeExtension_X0(bundle) ==
UNARY_RRR_0_OPCODE_X0) &&
(get_Opcode_X0(bundle) ==
RRR_0_OPCODE_X0)));
}
/*
* Check if nop or fnop at bundle's pipeline X1.
*/
static bool is_bundle_x1_nop(tilegx_bundle_bits bundle)
{
return (((get_UnaryOpcodeExtension_X1(bundle) ==
NOP_UNARY_OPCODE_X1) &&
(get_RRROpcodeExtension_X1(bundle) ==
UNARY_RRR_0_OPCODE_X1) &&
(get_Opcode_X1(bundle) ==
RRR_0_OPCODE_X1)) ||
((get_UnaryOpcodeExtension_X1(bundle) ==
FNOP_UNARY_OPCODE_X1) &&
(get_RRROpcodeExtension_X1(bundle) ==
UNARY_RRR_0_OPCODE_X1) &&
(get_Opcode_X1(bundle) ==
RRR_0_OPCODE_X1)));
}
/*
* Check if nop or fnop at bundle's Y0 pipeline.
*/
static bool is_bundle_y0_nop(tilegx_bundle_bits bundle)
{
return (((get_UnaryOpcodeExtension_Y0(bundle) ==
NOP_UNARY_OPCODE_Y0) &&
(get_RRROpcodeExtension_Y0(bundle) ==
UNARY_RRR_1_OPCODE_Y0) &&
(get_Opcode_Y0(bundle) ==
RRR_1_OPCODE_Y0)) ||
((get_UnaryOpcodeExtension_Y0(bundle) ==
FNOP_UNARY_OPCODE_Y0) &&
(get_RRROpcodeExtension_Y0(bundle) ==
UNARY_RRR_1_OPCODE_Y0) &&
(get_Opcode_Y0(bundle) ==
RRR_1_OPCODE_Y0)));
}
/*
* Check if nop or fnop at bundle's pipeline Y1.
*/
static bool is_bundle_y1_nop(tilegx_bundle_bits bundle)
{
return (((get_UnaryOpcodeExtension_Y1(bundle) ==
NOP_UNARY_OPCODE_Y1) &&
(get_RRROpcodeExtension_Y1(bundle) ==
UNARY_RRR_1_OPCODE_Y1) &&
(get_Opcode_Y1(bundle) ==
RRR_1_OPCODE_Y1)) ||
((get_UnaryOpcodeExtension_Y1(bundle) ==
FNOP_UNARY_OPCODE_Y1) &&
(get_RRROpcodeExtension_Y1(bundle) ==
UNARY_RRR_1_OPCODE_Y1) &&
(get_Opcode_Y1(bundle) ==
RRR_1_OPCODE_Y1)));
}
/*
* Test if a bundle's y0 and y1 pipelines are both nop or fnop.
*/
static bool is_y0_y1_nop(tilegx_bundle_bits bundle)
{
return is_bundle_y0_nop(bundle) && is_bundle_y1_nop(bundle);
}
/*
* Test if a bundle's x0 and x1 pipelines are both nop or fnop.
*/
static bool is_x0_x1_nop(tilegx_bundle_bits bundle)
{
return is_bundle_x0_nop(bundle) && is_bundle_x1_nop(bundle);
}
/*
* Find the destination, source registers of fault unalign access instruction
* at X1 or Y2. Also, allocate up to 3 scratch registers clob1, clob2 and
* clob3, which are guaranteed different from any register used in the fault
* bundle. r_alias is used to return if the other instructions other than the
* unalign load/store shares same register with ra, rb and rd.
*/
static void find_regs(tilegx_bundle_bits bundle, uint64_t *rd, uint64_t *ra,
uint64_t *rb, uint64_t *clob1, uint64_t *clob2,
uint64_t *clob3, bool *r_alias)
{
int i;
uint64_t reg;
uint64_t reg_map = 0, alias_reg_map = 0, map;
bool alias;
*ra = -1;
*rb = -1;
if (rd)
*rd = -1;
*clob1 = -1;
*clob2 = -1;
*clob3 = -1;
alias = false;
/*
* Parse fault bundle, find potential used registers and mark
* corresponding bits in reg_map and alias_map. These 2 bit maps
* are used to find the scratch registers and determine if there
* is register alais.
*/
if (bundle & TILEGX_BUNDLE_MODE_MASK) { /* Y Mode Bundle. */
reg = get_SrcA_Y2(bundle);
reg_map |= 1ULL << reg;
*ra = reg;
reg = get_SrcBDest_Y2(bundle);
reg_map |= 1ULL << reg;
if (rd) {
/* Load. */
*rd = reg;
alias_reg_map = (1ULL << *rd) | (1ULL << *ra);
} else {
/* Store. */
*rb = reg;
alias_reg_map = (1ULL << *ra) | (1ULL << *rb);
}
if (!is_bundle_y1_nop(bundle)) {
reg = get_SrcA_Y1(bundle);
reg_map |= (1ULL << reg);
map = (1ULL << reg);
reg = get_SrcB_Y1(bundle);
reg_map |= (1ULL << reg);
map |= (1ULL << reg);
reg = get_Dest_Y1(bundle);
reg_map |= (1ULL << reg);
map |= (1ULL << reg);
if (map & alias_reg_map)
alias = true;
}
if (!is_bundle_y0_nop(bundle)) {
reg = get_SrcA_Y0(bundle);
reg_map |= (1ULL << reg);
map = (1ULL << reg);
reg = get_SrcB_Y0(bundle);
reg_map |= (1ULL << reg);
map |= (1ULL << reg);
reg = get_Dest_Y0(bundle);
reg_map |= (1ULL << reg);
map |= (1ULL << reg);
if (map & alias_reg_map)
alias = true;
}
} else { /* X Mode Bundle. */
reg = get_SrcA_X1(bundle);
reg_map |= (1ULL << reg);
*ra = reg;
if (rd) {
/* Load. */
reg = get_Dest_X1(bundle);
reg_map |= (1ULL << reg);
*rd = reg;
alias_reg_map = (1ULL << *rd) | (1ULL << *ra);
} else {
/* Store. */
reg = get_SrcB_X1(bundle);
reg_map |= (1ULL << reg);
*rb = reg;
alias_reg_map = (1ULL << *ra) | (1ULL << *rb);
}
if (!is_bundle_x0_nop(bundle)) {
reg = get_SrcA_X0(bundle);
reg_map |= (1ULL << reg);
map = (1ULL << reg);
reg = get_SrcB_X0(bundle);
reg_map |= (1ULL << reg);
map |= (1ULL << reg);
reg = get_Dest_X0(bundle);
reg_map |= (1ULL << reg);
map |= (1ULL << reg);
if (map & alias_reg_map)
alias = true;
}
}
/*
* "alias" indicates if the unalign access registers have collision
* with others in the same bundle. We jsut simply test all register
* operands case (RRR), ignored the case with immidate. If a bundle
* has no register alias, we may do fixup in a simple or fast manner.
* So if an immidata field happens to hit with a register, we may end
* up fall back to the generic handling.
*/
*r_alias = alias;
/* Flip bits on reg_map. */
reg_map ^= -1ULL;
/* Scan reg_map lower 54(TREG_SP) bits to find 3 set bits. */
for (i = 0; i < TREG_SP; i++) {
if (reg_map & (0x1ULL << i)) {
if (*clob1 == -1) {
*clob1 = i;
} else if (*clob2 == -1) {
*clob2 = i;
} else if (*clob3 == -1) {
*clob3 = i;
return;
}
}
}
}
/*
* Sanity check for register ra, rb, rd, clob1/2/3. Return true if any of them
* is unexpected.
*/
static bool check_regs(uint64_t rd, uint64_t ra, uint64_t rb,
uint64_t clob1, uint64_t clob2, uint64_t clob3)
{
bool unexpected = false;
if ((ra >= 56) && (ra != TREG_ZERO))
unexpected = true;
if ((clob1 >= 56) || (clob2 >= 56) || (clob3 >= 56))
unexpected = true;
if (rd != -1) {
if ((rd >= 56) && (rd != TREG_ZERO))
unexpected = true;
} else {
if ((rb >= 56) && (rb != TREG_ZERO))
unexpected = true;
}
return unexpected;
}
#define GX_INSN_X0_MASK ((1ULL << 31) - 1)
#define GX_INSN_X1_MASK (((1ULL << 31) - 1) << 31)
#define GX_INSN_Y0_MASK ((0xFULL << 27) | (0xFFFFFULL))
#define GX_INSN_Y1_MASK (GX_INSN_Y0_MASK << 31)
#define GX_INSN_Y2_MASK ((0x7FULL << 51) | (0x7FULL << 20))
#ifdef __LITTLE_ENDIAN
#define GX_INSN_BSWAP(_bundle_) (_bundle_)
#else
#define GX_INSN_BSWAP(_bundle_) swab64(_bundle_)
#endif /* __LITTLE_ENDIAN */
/*
* __JIT_CODE(.) creates template bundles in .rodata.unalign_data section.
* The corresponding static function jix_x#_###(.) generates partial or
* whole bundle based on the template and given arguments.
*/
#define __JIT_CODE(_X_) \
asm (".pushsection .rodata.unalign_data, \"a\"\n" \
_X_"\n" \
".popsection\n")
__JIT_CODE("__unalign_jit_x1_mtspr: {mtspr 0, r0}");
static tilegx_bundle_bits jit_x1_mtspr(int spr, int reg)
{
extern tilegx_bundle_bits __unalign_jit_x1_mtspr;
return (GX_INSN_BSWAP(__unalign_jit_x1_mtspr) & GX_INSN_X1_MASK) |
create_MT_Imm14_X1(spr) | create_SrcA_X1(reg);
}
__JIT_CODE("__unalign_jit_x1_mfspr: {mfspr r0, 0}");
static tilegx_bundle_bits jit_x1_mfspr(int reg, int spr)
{
extern tilegx_bundle_bits __unalign_jit_x1_mfspr;
return (GX_INSN_BSWAP(__unalign_jit_x1_mfspr) & GX_INSN_X1_MASK) |
create_MF_Imm14_X1(spr) | create_Dest_X1(reg);
}
__JIT_CODE("__unalign_jit_x0_addi: {addi r0, r0, 0; iret}");
static tilegx_bundle_bits jit_x0_addi(int rd, int ra, int imm8)
{
extern tilegx_bundle_bits __unalign_jit_x0_addi;
return (GX_INSN_BSWAP(__unalign_jit_x0_addi) & GX_INSN_X0_MASK) |
create_Dest_X0(rd) | create_SrcA_X0(ra) |
create_Imm8_X0(imm8);
}
__JIT_CODE("__unalign_jit_x1_ldna: {ldna r0, r0}");
static tilegx_bundle_bits jit_x1_ldna(int rd, int ra)
{
extern tilegx_bundle_bits __unalign_jit_x1_ldna;
return (GX_INSN_BSWAP(__unalign_jit_x1_ldna) & GX_INSN_X1_MASK) |
create_Dest_X1(rd) | create_SrcA_X1(ra);
}
__JIT_CODE("__unalign_jit_x0_dblalign: {dblalign r0, r0 ,r0}");
static tilegx_bundle_bits jit_x0_dblalign(int rd, int ra, int rb)
{
extern tilegx_bundle_bits __unalign_jit_x0_dblalign;
return (GX_INSN_BSWAP(__unalign_jit_x0_dblalign) & GX_INSN_X0_MASK) |
create_Dest_X0(rd) | create_SrcA_X0(ra) |
create_SrcB_X0(rb);
}
__JIT_CODE("__unalign_jit_x1_iret: {iret}");
static tilegx_bundle_bits jit_x1_iret(void)
{
extern tilegx_bundle_bits __unalign_jit_x1_iret;
return GX_INSN_BSWAP(__unalign_jit_x1_iret) & GX_INSN_X1_MASK;
}
__JIT_CODE("__unalign_jit_x01_fnop: {fnop;fnop}");
static tilegx_bundle_bits jit_x0_fnop(void)
{
extern tilegx_bundle_bits __unalign_jit_x01_fnop;
return GX_INSN_BSWAP(__unalign_jit_x01_fnop) & GX_INSN_X0_MASK;
}
static tilegx_bundle_bits jit_x1_fnop(void)
{
extern tilegx_bundle_bits __unalign_jit_x01_fnop;
return GX_INSN_BSWAP(__unalign_jit_x01_fnop) & GX_INSN_X1_MASK;
}
__JIT_CODE("__unalign_jit_y2_dummy: {fnop; fnop; ld zero, sp}");
static tilegx_bundle_bits jit_y2_dummy(void)
{
extern tilegx_bundle_bits __unalign_jit_y2_dummy;
return GX_INSN_BSWAP(__unalign_jit_y2_dummy) & GX_INSN_Y2_MASK;
}
static tilegx_bundle_bits jit_y1_fnop(void)
{
extern tilegx_bundle_bits __unalign_jit_y2_dummy;
return GX_INSN_BSWAP(__unalign_jit_y2_dummy) & GX_INSN_Y1_MASK;
}
__JIT_CODE("__unalign_jit_x1_st1_add: {st1_add r1, r0, 0}");
static tilegx_bundle_bits jit_x1_st1_add(int ra, int rb, int imm8)
{
extern tilegx_bundle_bits __unalign_jit_x1_st1_add;
return (GX_INSN_BSWAP(__unalign_jit_x1_st1_add) &
(~create_SrcA_X1(-1)) &
GX_INSN_X1_MASK) | create_SrcA_X1(ra) |
create_SrcB_X1(rb) | create_Dest_Imm8_X1(imm8);
}
__JIT_CODE("__unalign_jit_x1_st: {crc32_8 r1, r0, r0; st r0, r0}");
static tilegx_bundle_bits jit_x1_st(int ra, int rb)
{
extern tilegx_bundle_bits __unalign_jit_x1_st;
return (GX_INSN_BSWAP(__unalign_jit_x1_st) & GX_INSN_X1_MASK) |
create_SrcA_X1(ra) | create_SrcB_X1(rb);
}
__JIT_CODE("__unalign_jit_x1_st_add: {st_add r1, r0, 0}");
static tilegx_bundle_bits jit_x1_st_add(int ra, int rb, int imm8)
{
extern tilegx_bundle_bits __unalign_jit_x1_st_add;
return (GX_INSN_BSWAP(__unalign_jit_x1_st_add) &
(~create_SrcA_X1(-1)) &
GX_INSN_X1_MASK) | create_SrcA_X1(ra) |
create_SrcB_X1(rb) | create_Dest_Imm8_X1(imm8);
}
__JIT_CODE("__unalign_jit_x1_ld: {crc32_8 r1, r0, r0; ld r0, r0}");
static tilegx_bundle_bits jit_x1_ld(int rd, int ra)
{
extern tilegx_bundle_bits __unalign_jit_x1_ld;
return (GX_INSN_BSWAP(__unalign_jit_x1_ld) & GX_INSN_X1_MASK) |
create_Dest_X1(rd) | create_SrcA_X1(ra);
}
__JIT_CODE("__unalign_jit_x1_ld_add: {ld_add r1, r0, 0}");
static tilegx_bundle_bits jit_x1_ld_add(int rd, int ra, int imm8)
{
extern tilegx_bundle_bits __unalign_jit_x1_ld_add;
return (GX_INSN_BSWAP(__unalign_jit_x1_ld_add) &
(~create_Dest_X1(-1)) &
GX_INSN_X1_MASK) | create_Dest_X1(rd) |
create_SrcA_X1(ra) | create_Imm8_X1(imm8);
}
__JIT_CODE("__unalign_jit_x0_bfexts: {bfexts r0, r0, 0, 0}");
static tilegx_bundle_bits jit_x0_bfexts(int rd, int ra, int bfs, int bfe)
{
extern tilegx_bundle_bits __unalign_jit_x0_bfexts;
return (GX_INSN_BSWAP(__unalign_jit_x0_bfexts) &
GX_INSN_X0_MASK) |
create_Dest_X0(rd) | create_SrcA_X0(ra) |
create_BFStart_X0(bfs) | create_BFEnd_X0(bfe);
}
__JIT_CODE("__unalign_jit_x0_bfextu: {bfextu r0, r0, 0, 0}");
static tilegx_bundle_bits jit_x0_bfextu(int rd, int ra, int bfs, int bfe)
{
extern tilegx_bundle_bits __unalign_jit_x0_bfextu;
return (GX_INSN_BSWAP(__unalign_jit_x0_bfextu) &
GX_INSN_X0_MASK) |
create_Dest_X0(rd) | create_SrcA_X0(ra) |
create_BFStart_X0(bfs) | create_BFEnd_X0(bfe);
}
__JIT_CODE("__unalign_jit_x1_addi: {bfextu r1, r1, 0, 0; addi r0, r0, 0}");
static tilegx_bundle_bits jit_x1_addi(int rd, int ra, int imm8)
{
extern tilegx_bundle_bits __unalign_jit_x1_addi;
return (GX_INSN_BSWAP(__unalign_jit_x1_addi) & GX_INSN_X1_MASK) |
create_Dest_X1(rd) | create_SrcA_X1(ra) |
create_Imm8_X1(imm8);
}
__JIT_CODE("__unalign_jit_x0_shrui: {shrui r0, r0, 0; iret}");
static tilegx_bundle_bits jit_x0_shrui(int rd, int ra, int imm6)
{
extern tilegx_bundle_bits __unalign_jit_x0_shrui;
return (GX_INSN_BSWAP(__unalign_jit_x0_shrui) &
GX_INSN_X0_MASK) |
create_Dest_X0(rd) | create_SrcA_X0(ra) |
create_ShAmt_X0(imm6);
}
__JIT_CODE("__unalign_jit_x0_rotli: {rotli r0, r0, 0; iret}");
static tilegx_bundle_bits jit_x0_rotli(int rd, int ra, int imm6)
{
extern tilegx_bundle_bits __unalign_jit_x0_rotli;
return (GX_INSN_BSWAP(__unalign_jit_x0_rotli) &
GX_INSN_X0_MASK) |
create_Dest_X0(rd) | create_SrcA_X0(ra) |
create_ShAmt_X0(imm6);
}
__JIT_CODE("__unalign_jit_x1_bnezt: {bnezt r0, __unalign_jit_x1_bnezt}");
static tilegx_bundle_bits jit_x1_bnezt(int ra, int broff)
{
extern tilegx_bundle_bits __unalign_jit_x1_bnezt;
return (GX_INSN_BSWAP(__unalign_jit_x1_bnezt) &
GX_INSN_X1_MASK) |
create_SrcA_X1(ra) | create_BrOff_X1(broff);
}
#undef __JIT_CODE
/*
* This function generates unalign fixup JIT.
*
* We first find unalign load/store instruction's destination, source
* registers: ra, rb and rd. and 3 scratch registers by calling
* find_regs(...). 3 scratch clobbers should not alias with any register
* used in the fault bundle. Then analyze the fault bundle to determine
* if it's a load or store, operand width, branch or address increment etc.
* At last generated JIT is copied into JIT code area in user space.
*/
static
void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
int align_ctl)
{
struct thread_info *info = current_thread_info();
struct unaligned_jit_fragment frag;
struct unaligned_jit_fragment *jit_code_area;
tilegx_bundle_bits bundle_2 = 0;
/* If bundle_2_enable = false, bundle_2 is fnop/nop operation. */
bool bundle_2_enable = true;
uint64_t ra, rb, rd = -1, clob1, clob2, clob3;
/*
* Indicate if the unalign access
* instruction's registers hit with
* others in the same bundle.
*/
bool alias = false;
bool load_n_store = true;
bool load_store_signed = false;
unsigned int load_store_size = 8;
bool y1_br = false; /* True, for a branch in same bundle at Y1.*/
int y1_br_reg = 0;
/* True for link operation. i.e. jalr or lnk at Y1 */
bool y1_lr = false;
int y1_lr_reg = 0;
bool x1_add = false;/* True, for load/store ADD instruction at X1*/
int x1_add_imm8 = 0;
bool unexpected = false;
int n = 0, k;
jit_code_area =
(struct unaligned_jit_fragment *)(info->unalign_jit_base);
memset((void *)&frag, 0, sizeof(frag));
/* 0: X mode, Otherwise: Y mode. */
if (bundle & TILEGX_BUNDLE_MODE_MASK) {
unsigned int mod, opcode;
if (get_Opcode_Y1(bundle) == RRR_1_OPCODE_Y1 &&
get_RRROpcodeExtension_Y1(bundle) ==
UNARY_RRR_1_OPCODE_Y1) {
opcode = get_UnaryOpcodeExtension_Y1(bundle);
/*
* Test "jalr", "jalrp", "jr", "jrp" instruction at Y1
* pipeline.
*/
switch (opcode) {
case JALR_UNARY_OPCODE_Y1:
case JALRP_UNARY_OPCODE_Y1:
y1_lr = true;
y1_lr_reg = 55; /* Link register. */
/* FALLTHROUGH */
case JR_UNARY_OPCODE_Y1:
case JRP_UNARY_OPCODE_Y1:
y1_br = true;
y1_br_reg = get_SrcA_Y1(bundle);
break;
case LNK_UNARY_OPCODE_Y1:
/* "lnk" at Y1 pipeline. */
y1_lr = true;
y1_lr_reg = get_Dest_Y1(bundle);
break;
}
}
opcode = get_Opcode_Y2(bundle);
mod = get_Mode(bundle);
/*
* bundle_2 is bundle after making Y2 as a dummy operation
* - ld zero, sp
*/
bundle_2 = (bundle & (~GX_INSN_Y2_MASK)) | jit_y2_dummy();
/* Make Y1 as fnop if Y1 is a branch or lnk operation. */
if (y1_br || y1_lr) {
bundle_2 &= ~(GX_INSN_Y1_MASK);
bundle_2 |= jit_y1_fnop();
}
if (is_y0_y1_nop(bundle_2))
bundle_2_enable = false;
if (mod == MODE_OPCODE_YC2) {
/* Store. */
load_n_store = false;
load_store_size = 1 << opcode;
load_store_signed = false;
find_regs(bundle, 0, &ra, &rb, &clob1, &clob2,
&clob3, &alias);
if (load_store_size > 8)
unexpected = true;
} else {
/* Load. */
load_n_store = true;
if (mod == MODE_OPCODE_YB2) {
switch (opcode) {
case LD_OPCODE_Y2:
load_store_signed = false;
load_store_size = 8;
break;
case LD4S_OPCODE_Y2:
load_store_signed = true;
load_store_size = 4;
break;
case LD4U_OPCODE_Y2:
load_store_signed = false;
load_store_size = 4;
break;
default:
unexpected = true;
}
} else if (mod == MODE_OPCODE_YA2) {
if (opcode == LD2S_OPCODE_Y2) {
load_store_signed = true;
load_store_size = 2;
} else if (opcode == LD2U_OPCODE_Y2) {
load_store_signed = false;
load_store_size = 2;
} else
unexpected = true;
} else
unexpected = true;
find_regs(bundle, &rd, &ra, &rb, &clob1, &clob2,
&clob3, &alias);
}
} else {
unsigned int opcode;
/* bundle_2 is bundle after making X1 as "fnop". */
bundle_2 = (bundle & (~GX_INSN_X1_MASK)) | jit_x1_fnop();
if (is_x0_x1_nop(bundle_2))
bundle_2_enable = false;
if (get_Opcode_X1(bundle) == RRR_0_OPCODE_X1) {
opcode = get_UnaryOpcodeExtension_X1(bundle);
if (get_RRROpcodeExtension_X1(bundle) ==
UNARY_RRR_0_OPCODE_X1) {
load_n_store = true;
find_regs(bundle, &rd, &ra, &rb, &clob1,
&clob2, &clob3, &alias);
switch (opcode) {
case LD_UNARY_OPCODE_X1:
load_store_signed = false;
load_store_size = 8;
break;
case LD4S_UNARY_OPCODE_X1:
load_store_signed = true;
/* FALLTHROUGH */
case LD4U_UNARY_OPCODE_X1:
load_store_size = 4;
break;
case LD2S_UNARY_OPCODE_X1:
load_store_signed = true;
/* FALLTHROUGH */
case LD2U_UNARY_OPCODE_X1:
load_store_size = 2;
break;
default:
unexpected = true;
}
} else {
load_n_store = false;
load_store_signed = false;
find_regs(bundle, 0, &ra, &rb,
&clob1, &clob2, &clob3,
&alias);
opcode = get_RRROpcodeExtension_X1(bundle);
switch (opcode) {
case ST_RRR_0_OPCODE_X1:
load_store_size = 8;
break;
case ST4_RRR_0_OPCODE_X1:
load_store_size = 4;
break;
case ST2_RRR_0_OPCODE_X1:
load_store_size = 2;
break;
default:
unexpected = true;
}
}
} else if (get_Opcode_X1(bundle) == IMM8_OPCODE_X1) {
load_n_store = true;
opcode = get_Imm8OpcodeExtension_X1(bundle);
switch (opcode) {
case LD_ADD_IMM8_OPCODE_X1:
load_store_size = 8;
break;
case LD4S_ADD_IMM8_OPCODE_X1:
load_store_signed = true;
/* FALLTHROUGH */
case LD4U_ADD_IMM8_OPCODE_X1:
load_store_size = 4;
break;
case LD2S_ADD_IMM8_OPCODE_X1:
load_store_signed = true;
/* FALLTHROUGH */
case LD2U_ADD_IMM8_OPCODE_X1:
load_store_size = 2;
break;
case ST_ADD_IMM8_OPCODE_X1:
load_n_store = false;
load_store_size = 8;
break;
case ST4_ADD_IMM8_OPCODE_X1:
load_n_store = false;
load_store_size = 4;
break;
case ST2_ADD_IMM8_OPCODE_X1:
load_n_store = false;
load_store_size = 2;
break;
default:
unexpected = true;
}
if (!unexpected) {
x1_add = true;
if (load_n_store)
x1_add_imm8 = get_Imm8_X1(bundle);
else
x1_add_imm8 = get_Dest_Imm8_X1(bundle);
}
find_regs(bundle, load_n_store ? (&rd) : NULL,
&ra, &rb, &clob1, &clob2, &clob3, &alias);
} else
unexpected = true;
}
/*
* Some sanity check for register numbers extracted from fault bundle.
*/
if (check_regs(rd, ra, rb, clob1, clob2, clob3) == true)
unexpected = true;
/* Give warning if register ra has an aligned address. */
if (!unexpected)
WARN_ON(!((load_store_size - 1) & (regs->regs[ra])));
/*
* Fault came from kernel space, here we only need take care of
* unaligned "get_user/put_user" macros defined in "uaccess.h".
* Basically, we will handle bundle like this:
* {ld/2u/4s rd, ra; movei rx, 0} or {st/2/4 ra, rb; movei rx, 0}
* (Refer to file "arch/tile/include/asm/uaccess.h" for details).
* For either load or store, byte-wise operation is performed by calling
* get_user() or put_user(). If the macro returns non-zero value,
* set the value to rx, otherwise set zero to rx. Finally make pc point
* to next bundle and return.
*/
if (EX1_PL(regs->ex1) != USER_PL) {
unsigned long rx = 0;
unsigned long x = 0, ret = 0;
if (y1_br || y1_lr || x1_add ||
(load_store_signed !=
(load_n_store && load_store_size == 4))) {
/* No branch, link, wrong sign-ext or load/store add. */
unexpected = true;
} else if (!unexpected) {
if (bundle & TILEGX_BUNDLE_MODE_MASK) {
/*
* Fault bundle is Y mode.
* Check if the Y1 and Y0 is the form of
* { movei rx, 0; nop/fnop }, if yes,
* find the rx.
*/
if ((get_Opcode_Y1(bundle) == ADDI_OPCODE_Y1)
&& (get_SrcA_Y1(bundle) == TREG_ZERO) &&
(get_Imm8_Y1(bundle) == 0) &&
is_bundle_y0_nop(bundle)) {
rx = get_Dest_Y1(bundle);
} else if ((get_Opcode_Y0(bundle) ==
ADDI_OPCODE_Y0) &&
(get_SrcA_Y0(bundle) == TREG_ZERO) &&
(get_Imm8_Y0(bundle) == 0) &&
is_bundle_y1_nop(bundle)) {
rx = get_Dest_Y0(bundle);
} else {
unexpected = true;
}
} else {
/*
* Fault bundle is X mode.
* Check if the X0 is 'movei rx, 0',
* if yes, find the rx.
*/
if ((get_Opcode_X0(bundle) == IMM8_OPCODE_X0)
&& (get_Imm8OpcodeExtension_X0(bundle) ==
ADDI_IMM8_OPCODE_X0) &&
(get_SrcA_X0(bundle) == TREG_ZERO) &&
(get_Imm8_X0(bundle) == 0)) {
rx = get_Dest_X0(bundle);
} else {
unexpected = true;
}
}
/* rx should be less than 56. */
if (!unexpected && (rx >= 56))
unexpected = true;
}
if (!search_exception_tables(regs->pc)) {
/* No fixup in the exception tables for the pc. */
unexpected = true;
}
if (unexpected) {
/* Unexpected unalign kernel fault. */
struct task_struct *tsk = validate_current();
bust_spinlocks(1);
show_regs(regs);
if (unlikely(tsk->pid < 2)) {
panic("Kernel unalign fault running %s!",
tsk->pid ? "init" : "the idle task");
}
#ifdef SUPPORT_DIE
die("Oops", regs);
#endif
bust_spinlocks(1);
do_group_exit(SIGKILL);
} else {
unsigned long i, b = 0;
unsigned char *ptr =
(unsigned char *)regs->regs[ra];
if (load_n_store) {
/* handle get_user(x, ptr) */
for (i = 0; i < load_store_size; i++) {
ret = get_user(b, ptr++);
if (!ret) {
/* Success! update x. */
#ifdef __LITTLE_ENDIAN
x |= (b << (8 * i));
#else
x <<= 8;
x |= b;
#endif /* __LITTLE_ENDIAN */
} else {
x = 0;
break;
}
}
/* Sign-extend 4-byte loads. */
if (load_store_size == 4)
x = (long)(int)x;
/* Set register rd. */
regs->regs[rd] = x;
/* Set register rx. */
regs->regs[rx] = ret;
/* Bump pc. */
regs->pc += 8;
} else {
/* Handle put_user(x, ptr) */
x = regs->regs[rb];
#ifdef __LITTLE_ENDIAN
b = x;
#else
/*
* Swap x in order to store x from low
* to high memory same as the
* little-endian case.
*/
switch (load_store_size) {
case 8:
b = swab64(x);
break;
case 4:
b = swab32(x);
break;
case 2:
b = swab16(x);
break;
}
#endif /* __LITTLE_ENDIAN */
for (i = 0; i < load_store_size; i++) {
ret = put_user(b, ptr++);
if (ret)
break;
/* Success! shift 1 byte. */
b >>= 8;
}
/* Set register rx. */
regs->regs[rx] = ret;
/* Bump pc. */
regs->pc += 8;
}
}
unaligned_fixup_count++;
if (unaligned_printk) {
pr_info("%s/%d. Unalign fixup for kernel access "
"to userspace %lx.",
current->comm, current->pid, regs->regs[ra]);
}
/* Done! Return to the exception handler. */
return;
}
if ((align_ctl == 0) || unexpected) {
siginfo_t info = {
.si_signo = SIGBUS,
.si_code = BUS_ADRALN,
.si_addr = (unsigned char __user *)0
};
if (unaligned_printk)
pr_info("Unalign bundle: unexp @%llx, %llx",
(unsigned long long)regs->pc,
(unsigned long long)bundle);
if (ra < 56) {
unsigned long uaa = (unsigned long)regs->regs[ra];
/* Set bus Address. */
info.si_addr = (unsigned char __user *)uaa;
}
unaligned_fixup_count++;
trace_unhandled_signal("unaligned fixup trap", regs,
(unsigned long)info.si_addr, SIGBUS);
force_sig_info(info.si_signo, &info, current);
return;
}
#ifdef __LITTLE_ENDIAN
#define UA_FIXUP_ADDR_DELTA 1
#define UA_FIXUP_BFEXT_START(_B_) 0
#define UA_FIXUP_BFEXT_END(_B_) (8 * (_B_) - 1)
#else /* __BIG_ENDIAN */
#define UA_FIXUP_ADDR_DELTA -1
#define UA_FIXUP_BFEXT_START(_B_) (64 - 8 * (_B_))
#define UA_FIXUP_BFEXT_END(_B_) 63
#endif /* __LITTLE_ENDIAN */
if ((ra != rb) && (rd != TREG_SP) && !alias &&
!y1_br && !y1_lr && !x1_add) {
/*
* Simple case: ra != rb and no register alias found,
* and no branch or link. This will be the majority.
* We can do a little better for simplae case than the
* generic scheme below.
*/
if (!load_n_store) {
/*
* Simple store: ra != rb, no need for scratch register.
* Just store and rotate to right bytewise.
*/
#ifdef __BIG_ENDIAN
frag.insn[n++] =
jit_x0_addi(ra, ra, load_store_size - 1) |
jit_x1_fnop();
#endif /* __BIG_ENDIAN */
for (k = 0; k < load_store_size; k++) {
/* Store a byte. */
frag.insn[n++] =
jit_x0_rotli(rb, rb, 56) |
jit_x1_st1_add(ra, rb,
UA_FIXUP_ADDR_DELTA);
}
#ifdef __BIG_ENDIAN
frag.insn[n] = jit_x1_addi(ra, ra, 1);
#else
frag.insn[n] = jit_x1_addi(ra, ra,
-1 * load_store_size);
#endif /* __LITTLE_ENDIAN */
if (load_store_size == 8) {
frag.insn[n] |= jit_x0_fnop();
} else if (load_store_size == 4) {
frag.insn[n] |= jit_x0_rotli(rb, rb, 32);
} else { /* = 2 */
frag.insn[n] |= jit_x0_rotli(rb, rb, 16);
}
n++;
if (bundle_2_enable)
frag.insn[n++] = bundle_2;
frag.insn[n++] = jit_x0_fnop() | jit_x1_iret();
} else {
if (rd == ra) {
/* Use two clobber registers: clob1/2. */
frag.insn[n++] =
jit_x0_addi(TREG_SP, TREG_SP, -16) |
jit_x1_fnop();
frag.insn[n++] =
jit_x0_addi(clob1, ra, 7) |
jit_x1_st_add(TREG_SP, clob1, -8);
frag.insn[n++] =
jit_x0_addi(clob2, ra, 0) |
jit_x1_st(TREG_SP, clob2);
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ldna(rd, ra);
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ldna(clob1, clob1);
/*
* Note: we must make sure that rd must not
* be sp. Recover clob1/2 from stack.
*/
frag.insn[n++] =
jit_x0_dblalign(rd, clob1, clob2) |
jit_x1_ld_add(clob2, TREG_SP, 8);
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ld_add(clob1, TREG_SP, 16);
} else {
/* Use one clobber register: clob1 only. */
frag.insn[n++] =
jit_x0_addi(TREG_SP, TREG_SP, -16) |
jit_x1_fnop();
frag.insn[n++] =
jit_x0_addi(clob1, ra, 7) |
jit_x1_st(TREG_SP, clob1);
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ldna(rd, ra);
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ldna(clob1, clob1);
/*
* Note: we must make sure that rd must not
* be sp. Recover clob1 from stack.
*/
frag.insn[n++] =
jit_x0_dblalign(rd, clob1, ra) |
jit_x1_ld_add(clob1, TREG_SP, 16);
}
if (bundle_2_enable)
frag.insn[n++] = bundle_2;
/*
* For non 8-byte load, extract corresponding bytes and
* signed extension.
*/
if (load_store_size == 4) {
if (load_store_signed)
frag.insn[n++] =
jit_x0_bfexts(
rd, rd,
UA_FIXUP_BFEXT_START(4),
UA_FIXUP_BFEXT_END(4)) |
jit_x1_fnop();
else
frag.insn[n++] =
jit_x0_bfextu(
rd, rd,
UA_FIXUP_BFEXT_START(4),
UA_FIXUP_BFEXT_END(4)) |
jit_x1_fnop();
} else if (load_store_size == 2) {
if (load_store_signed)
frag.insn[n++] =
jit_x0_bfexts(
rd, rd,
UA_FIXUP_BFEXT_START(2),
UA_FIXUP_BFEXT_END(2)) |
jit_x1_fnop();
else
frag.insn[n++] =
jit_x0_bfextu(
rd, rd,
UA_FIXUP_BFEXT_START(2),
UA_FIXUP_BFEXT_END(2)) |
jit_x1_fnop();
}
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_iret();
}
} else if (!load_n_store) {
/*
* Generic memory store cases: use 3 clobber registers.
*
* Alloc space for saveing clob2,1,3 on user's stack.
* register clob3 points to where clob2 saved, followed by
* clob1 and 3 from high to low memory.
*/
frag.insn[n++] =
jit_x0_addi(TREG_SP, TREG_SP, -32) |
jit_x1_fnop();
frag.insn[n++] =
jit_x0_addi(clob3, TREG_SP, 16) |
jit_x1_st_add(TREG_SP, clob3, 8);
#ifdef __LITTLE_ENDIAN
frag.insn[n++] =
jit_x0_addi(clob1, ra, 0) |
jit_x1_st_add(TREG_SP, clob1, 8);
#else
frag.insn[n++] =
jit_x0_addi(clob1, ra, load_store_size - 1) |
jit_x1_st_add(TREG_SP, clob1, 8);
#endif
if (load_store_size == 8) {
/*
* We save one byte a time, not for fast, but compact
* code. After each store, data source register shift
* right one byte. unchanged after 8 stores.
*/
frag.insn[n++] =
jit_x0_addi(clob2, TREG_ZERO, 7) |
jit_x1_st_add(TREG_SP, clob2, 16);
frag.insn[n++] =
jit_x0_rotli(rb, rb, 56) |
jit_x1_st1_add(clob1, rb, UA_FIXUP_ADDR_DELTA);
frag.insn[n++] =
jit_x0_addi(clob2, clob2, -1) |
jit_x1_bnezt(clob2, -1);
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_addi(clob2, y1_br_reg, 0);
} else if (load_store_size == 4) {
frag.insn[n++] =
jit_x0_addi(clob2, TREG_ZERO, 3) |
jit_x1_st_add(TREG_SP, clob2, 16);
frag.insn[n++] =
jit_x0_rotli(rb, rb, 56) |
jit_x1_st1_add(clob1, rb, UA_FIXUP_ADDR_DELTA);
frag.insn[n++] =
jit_x0_addi(clob2, clob2, -1) |
jit_x1_bnezt(clob2, -1);
/*
* same as 8-byte case, but need shift another 4
* byte to recover rb for 4-byte store.
*/
frag.insn[n++] = jit_x0_rotli(rb, rb, 32) |
jit_x1_addi(clob2, y1_br_reg, 0);
} else { /* =2 */
frag.insn[n++] =
jit_x0_addi(clob2, rb, 0) |
jit_x1_st_add(TREG_SP, clob2, 16);
for (k = 0; k < 2; k++) {
frag.insn[n++] =
jit_x0_shrui(rb, rb, 8) |
jit_x1_st1_add(clob1, rb,
UA_FIXUP_ADDR_DELTA);
}
frag.insn[n++] =
jit_x0_addi(rb, clob2, 0) |
jit_x1_addi(clob2, y1_br_reg, 0);
}
if (bundle_2_enable)
frag.insn[n++] = bundle_2;
if (y1_lr) {
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_mfspr(y1_lr_reg,
SPR_EX_CONTEXT_0_0);
}
if (y1_br) {
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_mtspr(SPR_EX_CONTEXT_0_0,
clob2);
}
if (x1_add) {
frag.insn[n++] =
jit_x0_addi(ra, ra, x1_add_imm8) |
jit_x1_ld_add(clob2, clob3, -8);
} else {
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ld_add(clob2, clob3, -8);
}
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ld_add(clob1, clob3, -8);
frag.insn[n++] = jit_x0_fnop() | jit_x1_ld(clob3, clob3);
frag.insn[n++] = jit_x0_fnop() | jit_x1_iret();
} else {
/*
* Generic memory load cases.
*
* Alloc space for saveing clob1,2,3 on user's stack.
* register clob3 points to where clob1 saved, followed
* by clob2 and 3 from high to low memory.
*/
frag.insn[n++] =
jit_x0_addi(TREG_SP, TREG_SP, -32) |
jit_x1_fnop();
frag.insn[n++] =
jit_x0_addi(clob3, TREG_SP, 16) |
jit_x1_st_add(TREG_SP, clob3, 8);
frag.insn[n++] =
jit_x0_addi(clob2, ra, 0) |
jit_x1_st_add(TREG_SP, clob2, 8);
if (y1_br) {
frag.insn[n++] =
jit_x0_addi(clob1, y1_br_reg, 0) |
jit_x1_st_add(TREG_SP, clob1, 16);
} else {
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_st_add(TREG_SP, clob1, 16);
}
if (bundle_2_enable)
frag.insn[n++] = bundle_2;
if (y1_lr) {
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_mfspr(y1_lr_reg,
SPR_EX_CONTEXT_0_0);
}
if (y1_br) {
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_mtspr(SPR_EX_CONTEXT_0_0,
clob1);
}
frag.insn[n++] =
jit_x0_addi(clob1, clob2, 7) |
jit_x1_ldna(rd, clob2);
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ldna(clob1, clob1);
frag.insn[n++] =
jit_x0_dblalign(rd, clob1, clob2) |
jit_x1_ld_add(clob1, clob3, -8);
if (x1_add) {
frag.insn[n++] =
jit_x0_addi(ra, ra, x1_add_imm8) |
jit_x1_ld_add(clob2, clob3, -8);
} else {
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ld_add(clob2, clob3, -8);
}
frag.insn[n++] =
jit_x0_fnop() |
jit_x1_ld(clob3, clob3);
if (load_store_size == 4) {
if (load_store_signed)
frag.insn[n++] =
jit_x0_bfexts(
rd, rd,
UA_FIXUP_BFEXT_START(4),
UA_FIXUP_BFEXT_END(4)) |
jit_x1_fnop();
else
frag.insn[n++] =
jit_x0_bfextu(
rd, rd,
UA_FIXUP_BFEXT_START(4),
UA_FIXUP_BFEXT_END(4)) |
jit_x1_fnop();
} else if (load_store_size == 2) {
if (load_store_signed)
frag.insn[n++] =
jit_x0_bfexts(
rd, rd,
UA_FIXUP_BFEXT_START(2),
UA_FIXUP_BFEXT_END(2)) |
jit_x1_fnop();
else
frag.insn[n++] =
jit_x0_bfextu(
rd, rd,
UA_FIXUP_BFEXT_START(2),
UA_FIXUP_BFEXT_END(2)) |
jit_x1_fnop();
}
frag.insn[n++] = jit_x0_fnop() | jit_x1_iret();
}
/* Max JIT bundle count is 14. */
WARN_ON(n > 14);
if (!unexpected) {
int status = 0;
int idx = (regs->pc >> 3) &
((1ULL << (PAGE_SHIFT - UNALIGN_JIT_SHIFT)) - 1);
frag.pc = regs->pc;
frag.bundle = bundle;
if (unaligned_printk) {
pr_info("%s/%d, Unalign fixup: pc=%lx "
"bundle=%lx %d %d %d %d %d %d %d %d.",
current->comm, current->pid,
(unsigned long)frag.pc,
(unsigned long)frag.bundle,
(int)alias, (int)rd, (int)ra,
(int)rb, (int)bundle_2_enable,
(int)y1_lr, (int)y1_br, (int)x1_add);
for (k = 0; k < n; k += 2)
pr_info("[%d] %016llx %016llx", k,
(unsigned long long)frag.insn[k],
(unsigned long long)frag.insn[k+1]);
}
/* Swap bundle byte order for big endian sys. */
#ifdef __BIG_ENDIAN
frag.bundle = GX_INSN_BSWAP(frag.bundle);
for (k = 0; k < n; k++)
frag.insn[k] = GX_INSN_BSWAP(frag.insn[k]);
#endif /* __BIG_ENDIAN */
status = copy_to_user((void __user *)&jit_code_area[idx],
&frag, sizeof(frag));
if (status) {
/* Fail to copy JIT into user land. send SIGSEGV. */
siginfo_t info = {
.si_signo = SIGSEGV,
.si_code = SEGV_MAPERR,
.si_addr = (void __user *)&jit_code_area[idx]
};
pr_warn("Unalign fixup: pid=%d %s jit_code_area=%llx",
current->pid, current->comm,
(unsigned long long)&jit_code_area[idx]);
trace_unhandled_signal("segfault in unalign fixup",
regs,
(unsigned long)info.si_addr,
SIGSEGV);
force_sig_info(info.si_signo, &info, current);
return;
}
/* Do a cheaper increment, not accurate. */
unaligned_fixup_count++;
__flush_icache_range((unsigned long)&jit_code_area[idx],
(unsigned long)&jit_code_area[idx] +
sizeof(frag));
/* Setup SPR_EX_CONTEXT_0_0/1 for returning to user program.*/
__insn_mtspr(SPR_EX_CONTEXT_0_0, regs->pc + 8);
__insn_mtspr(SPR_EX_CONTEXT_0_1, PL_ICS_EX1(USER_PL, 0));
/* Modify pc at the start of new JIT. */
regs->pc = (unsigned long)&jit_code_area[idx].insn[0];
/* Set ICS in SPR_EX_CONTEXT_K_1. */
regs->ex1 = PL_ICS_EX1(USER_PL, 1);
}
}
/*
* C function to generate unalign data JIT. Called from unalign data
* interrupt handler.
*
* First check if unalign fix is disabled or exception did not not come from
* user space or sp register points to unalign address, if true, generate a
* SIGBUS. Then map a page into user space as JIT area if it is not mapped
* yet. Genenerate JIT code by calling jit_bundle_gen(). After that return
* back to exception handler.
*
* The exception handler will "iret" to new generated JIT code after
* restoring caller saved registers. In theory, the JIT code will perform
* another "iret" to resume user's program.
*/
void do_unaligned(struct pt_regs *regs, int vecnum)
{
tilegx_bundle_bits __user *pc;
tilegx_bundle_bits bundle;
struct thread_info *info = current_thread_info();
int align_ctl;
/* Checks the per-process unaligned JIT flags */
align_ctl = unaligned_fixup;
switch (task_thread_info(current)->align_ctl) {
case PR_UNALIGN_NOPRINT:
align_ctl = 1;
break;
case PR_UNALIGN_SIGBUS:
align_ctl = 0;
break;
}
/* Enable iterrupt in order to access user land. */
local_irq_enable();
/*
* The fault came from kernel space. Two choices:
* (a) unaligned_fixup < 1, we will first call get/put_user fixup
* to return -EFAULT. If no fixup, simply panic the kernel.
* (b) unaligned_fixup >=1, we will try to fix the unaligned access
* if it was triggered by get_user/put_user() macros. Panic the
* kernel if it is not fixable.
*/
if (EX1_PL(regs->ex1) != USER_PL) {
if (align_ctl < 1) {
unaligned_fixup_count++;
/* If exception came from kernel, try fix it up. */
if (fixup_exception(regs)) {
if (unaligned_printk)
pr_info("Unalign fixup: %d %llx @%llx",
(int)unaligned_fixup,
(unsigned long long)regs->ex1,
(unsigned long long)regs->pc);
return;
}
/* Not fixable. Go panic. */
panic("Unalign exception in Kernel. pc=%lx",
regs->pc);
return;
} else {
/*
* Try to fix the exception. If we can't, panic the
* kernel.
*/
bundle = GX_INSN_BSWAP(
*((tilegx_bundle_bits *)(regs->pc)));
jit_bundle_gen(regs, bundle, align_ctl);
return;
}
}
/*
* Fault came from user with ICS or stack is not aligned.
* If so, we will trigger SIGBUS.
*/
if ((regs->sp & 0x7) || (regs->ex1) || (align_ctl < 0)) {
siginfo_t info = {
.si_signo = SIGBUS,
.si_code = BUS_ADRALN,
.si_addr = (unsigned char __user *)0
};
if (unaligned_printk)
pr_info("Unalign fixup: %d %llx @%llx",
(int)unaligned_fixup,
(unsigned long long)regs->ex1,
(unsigned long long)regs->pc);
unaligned_fixup_count++;
trace_unhandled_signal("unaligned fixup trap", regs, 0, SIGBUS);
force_sig_info(info.si_signo, &info, current);
return;
}
/* Read the bundle casued the exception! */
pc = (tilegx_bundle_bits __user *)(regs->pc);
if (get_user(bundle, pc) != 0) {
/* Probably never be here since pc is valid user address.*/
siginfo_t info = {
.si_signo = SIGSEGV,
.si_code = SEGV_MAPERR,
.si_addr = (void __user *)pc
};
pr_err("Couldn't read instruction at %p trying to step\n", pc);
trace_unhandled_signal("segfault in unalign fixup", regs,
(unsigned long)info.si_addr, SIGSEGV);
force_sig_info(info.si_signo, &info, current);
return;
}
if (!info->unalign_jit_base) {
void __user *user_page;
/*
* Allocate a page in userland.
* For 64-bit processes we try to place the mapping far
* from anything else that might be going on (specifically
* 64 GB below the top of the user address space). If it
* happens not to be possible to put it there, it's OK;
* the kernel will choose another location and we'll
* remember it for later.
*/
if (is_compat_task())
user_page = NULL;
else
user_page = (void __user *)(TASK_SIZE - (1UL << 36)) +
(current->pid << PAGE_SHIFT);
user_page = (void __user *) vm_mmap(NULL,
(unsigned long)user_page,
PAGE_SIZE,
PROT_EXEC | PROT_READ |
PROT_WRITE,
#ifdef CONFIG_HOMECACHE
MAP_CACHE_HOME_TASK |
#endif
MAP_PRIVATE |
MAP_ANONYMOUS,
0);
if (IS_ERR((void __force *)user_page)) {
pr_err("Out of kernel pages trying do_mmap.\n");
return;
}
/* Save the address in the thread_info struct */
info->unalign_jit_base = user_page;
if (unaligned_printk)
pr_info("Unalign bundle: %d:%d, allocate page @%llx",
raw_smp_processor_id(), current->pid,
(unsigned long long)user_page);
}
/* Generate unalign JIT */
jit_bundle_gen(regs, GX_INSN_BSWAP(bundle), align_ctl);
}
#endif /* __tilegx__ */
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