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linux/arch/riscv/include/asm/futex.h

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RISC-V: Add futex support. Here is an attempt to add the missing futex support. I started with the MIPS version of futex.h and modified it until I got it working. I tested it on a HiFive Unleashed running Fedora Core 29 using the fc29 4.15 version of the kernel. This was tested against the glibc testsuite, where it fixes 14 nptl related testsuite failures. That unfortunately only tests the cmpxchg support, so I also used the testcase at the end of https://lwn.net/Articles/148830/ which tests the atomic_op functionality, except that it doesn't verify that the operations are atomic, which they obviously are. This testcase runs successfully with the patch and fails without it. I'm not a kernel expert, so there could be details I got wrong here. I wasn't sure about the memory model support, so I used aqrl which seemed safest, and didn't add fences which seemed unnecessary. I'm not sure about the copyright statements, I left in Ralf Baechle's line because I started with his code. Checkpatch reports some style problems, but it is the same style as the MIPS futex.h, and the uses of ENOSYS appear correct even though it complains about them. I don't know if any of that matters. This patch was tested on qemu with the glibc nptl/tst-cond-except testcase, and the wake_op testcase from above. Signed-off-by: Jim Wilson <jimw@sifive.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 05:42:59 +08:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2006 Ralf Baechle (ralf@linux-mips.org)
* Copyright (c) 2018 Jim Wilson (jimw@sifive.com)
*/
riscv: clean up the macro format in each header file There are many different formats in each header now, such as _ASM_XXX_H, __ASM_XXX_H, _ASM_RISCV_XXX_H, RISCV_XXX_H, etc., This patch tries to unify the format by using _ASM_RISCV_XXX_H, because the most header use it now. This patch also adds the conditional to the headers if they lost it. Signed-off-by: Zong Li <zong.li@sifive.com> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-10-28 15:42:47 +08:00
#ifndef _ASM_RISCV_FUTEX_H
#define _ASM_RISCV_FUTEX_H
RISC-V: Add futex support. Here is an attempt to add the missing futex support. I started with the MIPS version of futex.h and modified it until I got it working. I tested it on a HiFive Unleashed running Fedora Core 29 using the fc29 4.15 version of the kernel. This was tested against the glibc testsuite, where it fixes 14 nptl related testsuite failures. That unfortunately only tests the cmpxchg support, so I also used the testcase at the end of https://lwn.net/Articles/148830/ which tests the atomic_op functionality, except that it doesn't verify that the operations are atomic, which they obviously are. This testcase runs successfully with the patch and fails without it. I'm not a kernel expert, so there could be details I got wrong here. I wasn't sure about the memory model support, so I used aqrl which seemed safest, and didn't add fences which seemed unnecessary. I'm not sure about the copyright statements, I left in Ralf Baechle's line because I started with his code. Checkpatch reports some style problems, but it is the same style as the MIPS futex.h, and the uses of ENOSYS appear correct even though it complains about them. I don't know if any of that matters. This patch was tested on qemu with the glibc nptl/tst-cond-except testcase, and the wake_op testcase from above. Signed-off-by: Jim Wilson <jimw@sifive.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 05:42:59 +08:00
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <linux/errno.h>
#include <asm/asm.h>
riscv: add nommu support The kernel runs in M-mode without using page tables, and thus can't run bare metal without help from additional firmware. Most of the patch is just stubbing out code not needed without page tables, but there is an interesting detail in the signals implementation: - The normal RISC-V syscall ABI only implements rt_sigreturn as VDSO entry point, but the ELF VDSO is not supported for nommu Linux. We instead copy the code to call the syscall onto the stack. In addition to enabling the nommu code a new defconfig for a small kernel image that can run in nommu mode on qemu is also provided, to run a kernel in qemu you can use the following command line: qemu-system-riscv64 -smp 2 -m 64 -machine virt -nographic \ -kernel arch/riscv/boot/loader \ -drive file=rootfs.ext2,format=raw,id=hd0 \ -device virtio-blk-device,drive=hd0 Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anup Patel <anup@brainfault.org> [paul.walmsley@sifive.com: updated to apply; add CONFIG_MMU guards around PCI_IOBASE definition to fix build issues; fixed checkpatch issues; move the PCI_IO_* and VMEMMAP address space macros along with the others; resolve sparse warning] Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-10-28 20:10:41 +08:00
/* We don't even really need the extable code, but for now keep it simple */
#ifndef CONFIG_MMU
#define __enable_user_access() do { } while (0)
#define __disable_user_access() do { } while (0)
#endif
RISC-V: Add futex support. Here is an attempt to add the missing futex support. I started with the MIPS version of futex.h and modified it until I got it working. I tested it on a HiFive Unleashed running Fedora Core 29 using the fc29 4.15 version of the kernel. This was tested against the glibc testsuite, where it fixes 14 nptl related testsuite failures. That unfortunately only tests the cmpxchg support, so I also used the testcase at the end of https://lwn.net/Articles/148830/ which tests the atomic_op functionality, except that it doesn't verify that the operations are atomic, which they obviously are. This testcase runs successfully with the patch and fails without it. I'm not a kernel expert, so there could be details I got wrong here. I wasn't sure about the memory model support, so I used aqrl which seemed safest, and didn't add fences which seemed unnecessary. I'm not sure about the copyright statements, I left in Ralf Baechle's line because I started with his code. Checkpatch reports some style problems, but it is the same style as the MIPS futex.h, and the uses of ENOSYS appear correct even though it complains about them. I don't know if any of that matters. This patch was tested on qemu with the glibc nptl/tst-cond-except testcase, and the wake_op testcase from above. Signed-off-by: Jim Wilson <jimw@sifive.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 05:42:59 +08:00
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
{ \
uintptr_t tmp; \
__enable_user_access(); \
__asm__ __volatile__ ( \
"1: " insn " \n" \
"2: \n" \
" .section .fixup,\"ax\" \n" \
" .balign 4 \n" \
"3: li %[r],%[e] \n" \
" jump 2b,%[t] \n" \
" .previous \n" \
" .section __ex_table,\"a\" \n" \
" .balign " RISCV_SZPTR " \n" \
" " RISCV_PTR " 1b, 3b \n" \
" .previous \n" \
: [r] "+r" (ret), [ov] "=&r" (oldval), \
[u] "+m" (*uaddr), [t] "=&r" (tmp) \
: [op] "Jr" (oparg), [e] "i" (-EFAULT) \
: "memory"); \
__disable_user_access(); \
}
static inline int
arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
{
int oldval = 0, ret = 0;
futex: arch_futex_atomic_op_inuser() calling conventions change Move access_ok() in and pagefault_enable()/pagefault_disable() out. Mechanical conversion only - some instances don't really need a separate access_ok() at all (e.g. the ones only using get_user()/put_user(), or architectures where access_ok() is always true); we'll deal with that in followups. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-02-16 23:17:27 +08:00
if (!access_ok(uaddr, sizeof(u32)))
return -EFAULT;
RISC-V: Add futex support. Here is an attempt to add the missing futex support. I started with the MIPS version of futex.h and modified it until I got it working. I tested it on a HiFive Unleashed running Fedora Core 29 using the fc29 4.15 version of the kernel. This was tested against the glibc testsuite, where it fixes 14 nptl related testsuite failures. That unfortunately only tests the cmpxchg support, so I also used the testcase at the end of https://lwn.net/Articles/148830/ which tests the atomic_op functionality, except that it doesn't verify that the operations are atomic, which they obviously are. This testcase runs successfully with the patch and fails without it. I'm not a kernel expert, so there could be details I got wrong here. I wasn't sure about the memory model support, so I used aqrl which seemed safest, and didn't add fences which seemed unnecessary. I'm not sure about the copyright statements, I left in Ralf Baechle's line because I started with his code. Checkpatch reports some style problems, but it is the same style as the MIPS futex.h, and the uses of ENOSYS appear correct even though it complains about them. I don't know if any of that matters. This patch was tested on qemu with the glibc nptl/tst-cond-except testcase, and the wake_op testcase from above. Signed-off-by: Jim Wilson <jimw@sifive.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 05:42:59 +08:00
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("amoadd.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("amoor.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("amoand.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, ~oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("amoxor.w.aqrl %[ov],%z[op],%[u]",
ret, oldval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
if (!ret)
*oval = oldval;
return ret;
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
u32 val;
uintptr_t tmp;
Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 10:57:57 +08:00
if (!access_ok(uaddr, sizeof(u32)))
RISC-V: Add futex support. Here is an attempt to add the missing futex support. I started with the MIPS version of futex.h and modified it until I got it working. I tested it on a HiFive Unleashed running Fedora Core 29 using the fc29 4.15 version of the kernel. This was tested against the glibc testsuite, where it fixes 14 nptl related testsuite failures. That unfortunately only tests the cmpxchg support, so I also used the testcase at the end of https://lwn.net/Articles/148830/ which tests the atomic_op functionality, except that it doesn't verify that the operations are atomic, which they obviously are. This testcase runs successfully with the patch and fails without it. I'm not a kernel expert, so there could be details I got wrong here. I wasn't sure about the memory model support, so I used aqrl which seemed safest, and didn't add fences which seemed unnecessary. I'm not sure about the copyright statements, I left in Ralf Baechle's line because I started with his code. Checkpatch reports some style problems, but it is the same style as the MIPS futex.h, and the uses of ENOSYS appear correct even though it complains about them. I don't know if any of that matters. This patch was tested on qemu with the glibc nptl/tst-cond-except testcase, and the wake_op testcase from above. Signed-off-by: Jim Wilson <jimw@sifive.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 05:42:59 +08:00
return -EFAULT;
__enable_user_access();
__asm__ __volatile__ (
"1: lr.w.aqrl %[v],%[u] \n"
" bne %[v],%z[ov],3f \n"
"2: sc.w.aqrl %[t],%z[nv],%[u] \n"
" bnez %[t],1b \n"
"3: \n"
" .section .fixup,\"ax\" \n"
" .balign 4 \n"
"4: li %[r],%[e] \n"
" jump 3b,%[t] \n"
" .previous \n"
" .section __ex_table,\"a\" \n"
" .balign " RISCV_SZPTR " \n"
" " RISCV_PTR " 1b, 4b \n"
" " RISCV_PTR " 2b, 4b \n"
" .previous \n"
: [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp)
: [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "i" (-EFAULT)
: "memory");
__disable_user_access();
*uval = val;
return ret;
}
riscv: clean up the macro format in each header file There are many different formats in each header now, such as _ASM_XXX_H, __ASM_XXX_H, _ASM_RISCV_XXX_H, RISCV_XXX_H, etc., This patch tries to unify the format by using _ASM_RISCV_XXX_H, because the most header use it now. This patch also adds the conditional to the headers if they lost it. Signed-off-by: Zong Li <zong.li@sifive.com> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-10-28 15:42:47 +08:00
#endif /* _ASM_RISCV_FUTEX_H */