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arm64: remove __exception annotations 

Since commit 7326749801 ("arm64: unwind: reference pt_regs via embedded
stack frame") arm64 has not used the __exception annotation to dump
the pt_regs during stack tracing. in_exception_text() has no callers.

This annotation is only used to blacklist kprobes, it means the same as
__kprobes.

Section annotations like this require the functions to be grouped
together between the start/end markers, and placed according to
the linker script. For kprobes we also have NOKPROBE_SYMBOL() which
logs the symbol address in a section that kprobes parses and
blacklists at boot.

Using NOKPROBE_SYMBOL() instead lets kprobes publish the list of
blacklisted symbols, and saves us from having an arm64 specific
spelling of __kprobes.

do_debug_exception() already has a NOKPROBE_SYMBOL() annotation.

Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
James Morse 2019-10-25 17:42:10 +01:00 committed by Catalin Marinas
parent 4f5cafb5cb
commit b6e43c0e31
6 changed files with 26 additions and 39 deletions
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4
arch/arm64/include/asm/exception.h
View File

@ -8,14 +8,14 @@
#define __ASM_EXCEPTION_H
#include <asm/esr.h>
#include <asm/kprobes.h>
#include <linux/interrupt.h>
#define __exception __attribute__((section(".exception.text")))
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
#define __exception_irq_entry __irq_entry
#else
#define __exception_irq_entry __exception
#define __exception_irq_entry __kprobes
#endif
static inline u32 disr_to_esr(u64 disr)

10
arch/arm64/include/asm/traps.h
View File

@ -42,16 +42,6 @@ static inline int __in_irqentry_text(unsigned long ptr)
ptr < (unsigned long)&__irqentry_text_end;
}
static inline int in_exception_text(unsigned long ptr)
{
int in;
in = ptr >= (unsigned long)&__exception_text_start &&
ptr < (unsigned long)&__exception_text_end;
return in ? : __in_irqentry_text(ptr);
}
static inline int in_entry_text(unsigned long ptr)
{
return ptr >= (unsigned long)&__entry_text_start &&

4
arch/arm64/kernel/probes/kprobes.c
View File

@ -455,10 +455,6 @@ int __init arch_populate_kprobe_blacklist(void)
(unsigned long)__irqentry_text_end);
if (ret)
return ret;
ret = kprobe_add_area_blacklist((unsigned long)__exception_text_start,
(unsigned long)__exception_text_end);
if (ret)
return ret;
ret = kprobe_add_area_blacklist((unsigned long)__idmap_text_start,
(unsigned long)__idmap_text_end);
if (ret)

10
arch/arm64/kernel/traps.c
View File

@ -35,6 +35,7 @@
#include <asm/debug-monitors.h>
#include <asm/esr.h>
#include <asm/insn.h>
#include <asm/kprobes.h>
#include <asm/traps.h>
#include <asm/smp.h>
#include <asm/stack_pointer.h>
@ -393,7 +394,7 @@ void arm64_notify_segfault(unsigned long addr)
force_signal_inject(SIGSEGV, code, addr);
}
asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
asmlinkage void do_undefinstr(struct pt_regs *regs)
{
/* check for AArch32 breakpoint instructions */
if (!aarch32_break_handler(regs))
@ -405,6 +406,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
BUG_ON(!user_mode(regs));
force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
}
NOKPROBE_SYMBOL(do_undefinstr);
#define __user_cache_maint(insn, address, res) \
if (address >= user_addr_max()) { \
@ -667,7 +669,7 @@ static const struct sys64_hook cp15_64_hooks[] = {
{},
};
asmlinkage void __exception do_cp15instr(unsigned int esr, struct pt_regs *regs)
asmlinkage void do_cp15instr(unsigned int esr, struct pt_regs *regs)
{
const struct sys64_hook *hook, *hook_base;
@ -705,9 +707,10 @@ asmlinkage void __exception do_cp15instr(unsigned int esr, struct pt_regs *regs)
*/
do_undefinstr(regs);
}
NOKPROBE_SYMBOL(do_cp15instr);
#endif
asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
asmlinkage void do_sysinstr(unsigned int esr, struct pt_regs *regs)
{
const struct sys64_hook *hook;
@ -724,6 +727,7 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
*/
do_undefinstr(regs);
}
NOKPROBE_SYMBOL(do_sysinstr);
static const char *esr_class_str[] = {
[0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",

3
arch/arm64/kernel/vmlinux.lds.S
View File

@ -111,9 +111,6 @@ SECTIONS
}
.text : { /* Real text segment */
_stext = .; /* Text and read-only data */
__exception_text_start = .;
*(.exception.text)
__exception_text_end = .;
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
ENTRY_TEXT

34
arch/arm64/mm/fault.c
View File

@ -33,6 +33,7 @@
#include <asm/debug-monitors.h>
#include <asm/esr.h>
#include <asm/kasan.h>
#include <asm/kprobes.h>
#include <asm/sysreg.h>
#include <asm/system_misc.h>
#include <asm/pgtable.h>
@ -732,8 +733,8 @@ static const struct fault_info fault_info[] = {
{ do_bad, SIGKILL, SI_KERNEL, "unknown 63" },
};
asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
asmlinkage void do_mem_abort(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
const struct fault_info *inf = esr_to_fault_info(esr);
@ -749,16 +750,17 @@ asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
arm64_notify_die(inf->name, regs,
inf->sig, inf->code, (void __user *)addr, esr);
}
NOKPROBE_SYMBOL(do_mem_abort);
asmlinkage void __exception do_el0_irq_bp_hardening(void)
asmlinkage void do_el0_irq_bp_hardening(void)
{
/* PC has already been checked in entry.S */
arm64_apply_bp_hardening();
}
NOKPROBE_SYMBOL(do_el0_irq_bp_hardening);
asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr,
unsigned int esr,
struct pt_regs *regs)
asmlinkage void do_el0_ia_bp_hardening(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
/*
* We've taken an instruction abort from userspace and not yet
@ -771,11 +773,10 @@ asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr,
local_daif_restore(DAIF_PROCCTX);
do_mem_abort(addr, esr, regs);
}
NOKPROBE_SYMBOL(do_el0_ia_bp_hardening);
asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
unsigned int esr,
struct pt_regs *regs)
asmlinkage void do_sp_pc_abort(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
if (user_mode(regs)) {
if (!is_ttbr0_addr(instruction_pointer(regs)))
@ -786,6 +787,7 @@ asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
arm64_notify_die("SP/PC alignment exception", regs,
SIGBUS, BUS_ADRALN, (void __user *)addr, esr);
}
NOKPROBE_SYMBOL(do_sp_pc_abort);
int __init early_brk64(unsigned long addr, unsigned int esr,
struct pt_regs *regs);
@ -868,8 +870,7 @@ NOKPROBE_SYMBOL(debug_exception_exit);
#ifdef CONFIG_ARM64_ERRATUM_1463225
DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
static int __exception
cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
{
if (user_mode(regs))
return 0;
@ -888,16 +889,15 @@ cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
return 1;
}
#else
static int __exception
cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
{
return 0;
}
#endif /* CONFIG_ARM64_ERRATUM_1463225 */
NOKPROBE_SYMBOL(cortex_a76_erratum_1463225_debug_handler);
asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint,
unsigned int esr,
struct pt_regs *regs)
asmlinkage void do_debug_exception(unsigned long addr_if_watchpoint,
unsigned int esr, struct pt_regs *regs)
{
const struct fault_info *inf = esr_to_debug_fault_info(esr);
unsigned long pc = instruction_pointer(regs);