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linux/arch/arm64/kernel/signal32.c
Arnd Bergmann d2a4a07190 arm64: rework compat syscall macros 
The generated asm/unistd_compat_32.h header file now contains
macros that can be used directly in the vdso and the signal
trampolines, so remove the duplicate definitions.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-07-10 14:23:38 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Based on arch/arm/kernel/signal.c
*
* Copyright (C) 1995-2009 Russell King
* Copyright (C) 2012 ARM Ltd.
* Modified by Will Deacon <will.deacon@arm.com>
*/
#include <linux/compat.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/ratelimit.h>
#include <asm/esr.h>
#include <asm/fpsimd.h>
#include <asm/signal32.h>
#include <asm/traps.h>
#include <linux/uaccess.h>
#include <asm/unistd_compat_32.h>
#include <asm/vdso.h>
struct compat_vfp_sigframe {
compat_ulong_t magic;
compat_ulong_t size;
struct compat_user_vfp {
compat_u64 fpregs[32];
compat_ulong_t fpscr;
} ufp;
struct compat_user_vfp_exc {
compat_ulong_t fpexc;
compat_ulong_t fpinst;
compat_ulong_t fpinst2;
} ufp_exc;
} __attribute__((__aligned__(8)));
#define VFP_MAGIC 0x56465001
#define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe)
#define FSR_WRITE_SHIFT (11)
struct compat_aux_sigframe {
struct compat_vfp_sigframe vfp;
/* Something that isn't a valid magic number for any coprocessor. */
unsigned long end_magic;
} __attribute__((__aligned__(8)));
static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
{
compat_sigset_t cset;
cset.sig[0] = set->sig[0] & 0xffffffffull;
cset.sig[1] = set->sig[0] >> 32;
return copy_to_user(uset, &cset, sizeof(*uset));
}
static inline int get_sigset_t(sigset_t *set,
const compat_sigset_t __user *uset)
{
compat_sigset_t s32;
if (copy_from_user(&s32, uset, sizeof(*uset)))
return -EFAULT;
set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
return 0;
}
/*
* VFP save/restore code.
*
* We have to be careful with endianness, since the fpsimd context-switch
* code operates on 128-bit (Q) register values whereas the compat ABI
* uses an array of 64-bit (D) registers. Consequently, we need to swap
* the two halves of each Q register when running on a big-endian CPU.
*/
union __fpsimd_vreg {
__uint128_t raw;
struct {
#ifdef __AARCH64EB__
u64 hi;
u64 lo;
#else
u64 lo;
u64 hi;
#endif
};
};
static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
{
struct user_fpsimd_state const *fpsimd =
&current->thread.uw.fpsimd_state;
compat_ulong_t magic = VFP_MAGIC;
compat_ulong_t size = VFP_STORAGE_SIZE;
compat_ulong_t fpscr, fpexc;
int i, err = 0;
/*
* Save the hardware registers to the fpsimd_state structure.
* Note that this also saves V16-31, which aren't visible
* in AArch32.
*/
fpsimd_signal_preserve_current_state();
/* Place structure header on the stack */
__put_user_error(magic, &frame->magic, err);
__put_user_error(size, &frame->size, err);
/*
* Now copy the FP registers. Since the registers are packed,
* we can copy the prefix we want (V0-V15) as it is.
*/
for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) {
union __fpsimd_vreg vreg = {
.raw = fpsimd->vregs[i >> 1],
};
__put_user_error(vreg.lo, &frame->ufp.fpregs[i], err);
__put_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err);
}
/* Create an AArch32 fpscr from the fpsr and the fpcr. */
fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) |
(fpsimd->fpcr & VFP_FPSCR_CTRL_MASK);
__put_user_error(fpscr, &frame->ufp.fpscr, err);
/*
* The exception register aren't available so we fake up a
* basic FPEXC and zero everything else.
*/
fpexc = (1 << 30);
__put_user_error(fpexc, &frame->ufp_exc.fpexc, err);
__put_user_error(0, &frame->ufp_exc.fpinst, err);
__put_user_error(0, &frame->ufp_exc.fpinst2, err);
return err ? -EFAULT : 0;
}
static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
{
struct user_fpsimd_state fpsimd;
compat_ulong_t magic = VFP_MAGIC;
compat_ulong_t size = VFP_STORAGE_SIZE;
compat_ulong_t fpscr;
int i, err = 0;
__get_user_error(magic, &frame->magic, err);
__get_user_error(size, &frame->size, err);
if (err)
return -EFAULT;
if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
return -EINVAL;
/* Copy the FP registers into the start of the fpsimd_state. */
for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) {
union __fpsimd_vreg vreg;
__get_user_error(vreg.lo, &frame->ufp.fpregs[i], err);
__get_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err);
fpsimd.vregs[i >> 1] = vreg.raw;
}
/* Extract the fpsr and the fpcr from the fpscr */
__get_user_error(fpscr, &frame->ufp.fpscr, err);
fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK;
fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
/*
* We don't need to touch the exception register, so
* reload the hardware state.
*/
if (!err)
fpsimd_update_current_state(&fpsimd);
return err ? -EFAULT : 0;
}
static int compat_restore_sigframe(struct pt_regs *regs,
struct compat_sigframe __user *sf)
{
int err;
sigset_t set;
struct compat_aux_sigframe __user *aux;
unsigned long psr;
err = get_sigset_t(&set, &sf->uc.uc_sigmask);
if (err == 0)
set_current_blocked(&set);
__get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
__get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
__get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
__get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
__get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
__get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
__get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
__get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
__get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
__get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
__get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
__get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
__get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
__get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
__get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
__get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
__get_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err);
regs->pstate = compat_psr_to_pstate(psr);
/*
* Avoid compat_sys_sigreturn() restarting.
*/
forget_syscall(regs);
err |= !valid_user_regs(&regs->user_regs, current);
aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
if (err == 0 && system_supports_fpsimd())
err |= compat_restore_vfp_context(&aux->vfp);
return err;
}
COMPAT_SYSCALL_DEFINE0(sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct compat_sigframe __user *frame;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
/*
* Since we stacked the signal on a 64-bit boundary,
* then 'sp' should be word aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->compat_sp & 7)
goto badframe;
frame = (struct compat_sigframe __user *)regs->compat_sp;
if (!access_ok(frame, sizeof (*frame)))
goto badframe;
if (compat_restore_sigframe(regs, frame))
goto badframe;
return regs->regs[0];
badframe:
arm64_notify_segfault(regs->compat_sp);
return 0;
}
COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct compat_rt_sigframe __user *frame;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
/*
* Since we stacked the signal on a 64-bit boundary,
* then 'sp' should be word aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->compat_sp & 7)
goto badframe;
frame = (struct compat_rt_sigframe __user *)regs->compat_sp;
if (!access_ok(frame, sizeof (*frame)))
goto badframe;
if (compat_restore_sigframe(regs, &frame->sig))
goto badframe;
if (compat_restore_altstack(&frame->sig.uc.uc_stack))
goto badframe;
return regs->regs[0];
badframe:
arm64_notify_segfault(regs->compat_sp);
return 0;
}
static void __user *compat_get_sigframe(struct ksignal *ksig,
struct pt_regs *regs,
int framesize)
{
compat_ulong_t sp = sigsp(regs->compat_sp, ksig);
void __user *frame;
/*
* ATPCS B01 mandates 8-byte alignment
*/
frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7));
/*
* Check that we can actually write to the signal frame.
*/
if (!access_ok(frame, framesize))
frame = NULL;
return frame;
}
static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
compat_ulong_t __user *rc, void __user *frame,
int usig)
{
compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler);
compat_ulong_t retcode;
compat_ulong_t spsr = regs->pstate & ~(PSR_f | PSR_AA32_E_BIT);
int thumb;
/* Check if the handler is written for ARM or Thumb */
thumb = handler & 1;
if (thumb)
spsr |= PSR_AA32_T_BIT;
else
spsr &= ~PSR_AA32_T_BIT;
/* The IT state must be cleared for both ARM and Thumb-2 */
spsr &= ~PSR_AA32_IT_MASK;
/* Restore the original endianness */
spsr |= PSR_AA32_ENDSTATE;
if (ka->sa.sa_flags & SA_RESTORER) {
retcode = ptr_to_compat(ka->sa.sa_restorer);
} else {
/* Set up sigreturn pointer */
unsigned int idx = thumb << 1;
if (ka->sa.sa_flags & SA_SIGINFO)
idx += 3;
retcode = (unsigned long)current->mm->context.sigpage +
(idx << 2) + thumb;
}
regs->regs[0] = usig;
regs->compat_sp = ptr_to_compat(frame);
regs->compat_lr = retcode;
regs->pc = handler;
regs->pstate = spsr;
}
static int compat_setup_sigframe(struct compat_sigframe __user *sf,
struct pt_regs *regs, sigset_t *set)
{
struct compat_aux_sigframe __user *aux;
unsigned long psr = pstate_to_compat_psr(regs->pstate);
int err = 0;
__put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
__put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
__put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
__put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
__put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
__put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
__put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
__put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
__put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
__put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
__put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
__put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
__put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
__put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
__put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
__put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
__put_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err);
__put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err);
/* set the compat FSR WnR */
__put_user_error(!!(current->thread.fault_code & ESR_ELx_WNR) <<
FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err);
__put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
err |= put_sigset_t(&sf->uc.uc_sigmask, set);
aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
if (err == 0 && system_supports_fpsimd())
err |= compat_preserve_vfp_context(&aux->vfp);
__put_user_error(0, &aux->end_magic, err);
return err;
}
/*
* 32-bit signal handling routines called from signal.c
*/
int compat_setup_rt_frame(int usig, struct ksignal *ksig,
sigset_t *set, struct pt_regs *regs)
{
struct compat_rt_sigframe __user *frame;
int err = 0;
frame = compat_get_sigframe(ksig, regs, sizeof(*frame));
if (!frame)
return 1;
err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
__put_user_error(0, &frame->sig.uc.uc_flags, err);
__put_user_error(0, &frame->sig.uc.uc_link, err);
err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp);
err |= compat_setup_sigframe(&frame->sig, regs, set);
if (err == 0) {
compat_setup_return(regs, &ksig->ka, frame->sig.retcode, frame, usig);
regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info;
regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc;
}
return err;
}
int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct compat_sigframe __user *frame;
int err = 0;
frame = compat_get_sigframe(ksig, regs, sizeof(*frame));
if (!frame)
return 1;
__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
err |= compat_setup_sigframe(frame, regs, set);
if (err == 0)
compat_setup_return(regs, &ksig->ka, frame->retcode, frame, usig);
return err;
}
void compat_setup_restart_syscall(struct pt_regs *regs)
{
regs->regs[7] = __NR_compat32_restart_syscall;
}
/*
* Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
* changes likely come with new fields that should be added below.
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
static_assert(NSIGSYS == 2);
static_assert(sizeof(compat_siginfo_t) == 128);
static_assert(__alignof__(compat_siginfo_t) == 4);
static_assert(offsetof(compat_siginfo_t, si_signo) == 0x00);
static_assert(offsetof(compat_siginfo_t, si_errno) == 0x04);
static_assert(offsetof(compat_siginfo_t, si_code) == 0x08);
static_assert(offsetof(compat_siginfo_t, si_pid) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_uid) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_tid) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_overrun) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_status) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_utime) == 0x18);
static_assert(offsetof(compat_siginfo_t, si_stime) == 0x1c);
static_assert(offsetof(compat_siginfo_t, si_value) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_int) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_ptr) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_addr) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_lower) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_upper) == 0x18);
static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_perf_data) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_perf_type) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_perf_flags) == 0x18);
static_assert(offsetof(compat_siginfo_t, si_band) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_fd) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_call_addr) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_syscall) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_arch) == 0x14);
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