[RFC PATCH v1 14/19] powerpc/signal32: Switch save_user_regs() and save_tm_user_regs() to user_access_begin() logic

From: Christophe Leroy
Date: Wed Aug 12 2020 - 08:06:35 EST

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/kernel/signal_32.c | 168 ++++++++++++++++----------------
1 file changed, 84 insertions(+), 84 deletions(-)

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 2c3d5d4400ec..0d076c2a9f6c 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -98,7 +98,7 @@ static inline int get_sigset_t(sigset_t *set,
#define to_user_ptr(p) ptr_to_compat(p)
#define from_user_ptr(p) compat_ptr(p)

-static inline int save_general_regs(struct pt_regs *regs,
+static __always_inline int save_general_regs(struct pt_regs *regs,
struct mcontext __user *frame)
{
elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
@@ -113,10 +113,12 @@ static inline int save_general_regs(struct pt_regs *regs,
else
val = gregs[i];

- if (__put_user(val, &frame->mc_gregs[i]))
- return -EFAULT;
+ unsafe_put_user(val, &frame->mc_gregs[i], failed);
}
return 0;
+
+failed:
+ return 1;
}

static inline int restore_general_regs(struct pt_regs *regs,
@@ -151,11 +153,15 @@ static inline int get_sigset_t(sigset_t *set, const sigset_t __user *uset)
#define to_user_ptr(p) ((unsigned long)(p))
#define from_user_ptr(p) ((void __user *)(p))

-static inline int save_general_regs(struct pt_regs *regs,
+static __always_inline int save_general_regs(struct pt_regs *regs,
struct mcontext __user *frame)
{
WARN_ON(!FULL_REGS(regs));
- return __copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE);
+ unsafe_copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE, failed);
+ return 0;
+
+failed:
+ return 1;
}

static inline int restore_general_regs(struct pt_regs *regs,
@@ -258,16 +264,18 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
flush_spe_to_thread(current);
#endif

+ if (!user_write_access_begin(frame, sizeof(*frame)))
+ return 1;
+
/* save general registers */
if (save_general_regs(regs, frame))
- return 1;
+ goto failed;

#ifdef CONFIG_ALTIVEC
/* save altivec registers */
if (current->thread.used_vr) {
- if (__copy_to_user(&frame->mc_vregs, &current->thread.vr_state,
- ELF_NVRREG * sizeof(vector128)))
- return 1;
+ unsafe_copy_to_user(&frame->mc_vregs, &current->thread.vr_state,
+ ELF_NVRREG * sizeof(vector128), failed);
/* set MSR_VEC in the saved MSR value to indicate that
frame->mc_vregs contains valid data */
msr |= MSR_VEC;
@@ -280,11 +288,9 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
* most significant bits of that same vector. --BenH
* Note that the current VRSAVE value is in the SPR at this point.
*/
- if (__put_user(current->thread.vrsave, (u32 __user *)&frame->mc_vregs[32]))
- return 1;
+ unsafe_put_user(current->thread.vrsave, (u32 __user *)&frame->mc_vregs[32], failed);
#endif /* CONFIG_ALTIVEC */
- if (copy_fpr_to_user(&frame->mc_fregs, current))
- return 1;
+ unsafe_copy_fpr_to_user(&frame->mc_fregs, current, failed);

/*
* Clear the MSR VSX bit to indicate there is no valid state attached
@@ -299,17 +305,15 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
* contains valid data
*/
if (current->thread.used_vsr && ctx_has_vsx_region) {
- if (copy_vsx_to_user(&frame->mc_vsregs, current))
- return 1;
+ unsafe_copy_vsx_to_user(&frame->mc_vsregs, current, failed);
msr |= MSR_VSX;
}
#endif /* CONFIG_VSX */
#ifdef CONFIG_SPE
/* save spe registers */
if (current->thread.used_spe) {
- if (__copy_to_user(&frame->mc_vregs, current->thread.evr,
- ELF_NEVRREG * sizeof(u32)))
- return 1;
+ unsafe_copy_to_user(&frame->mc_vregs, current->thread.evr,
+ ELF_NEVRREG * sizeof(u32)), failed);
/* set MSR_SPE in the saved MSR value to indicate that
frame->mc_vregs contains valid data */
msr |= MSR_SPE;
@@ -317,19 +321,18 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
/* else assert((regs->msr & MSR_SPE) == 0) */

/* We always copy to/from spefscr */
- if (__put_user(current->thread.spefscr, (u32 __user *)&frame->mc_vregs + ELF_NEVRREG))
- return 1;
+ unsafe_put_user(current->thread.spefscr, (u32 __user *)&frame->mc_vregs + ELF_NEVRREG, failed);
#endif /* CONFIG_SPE */

- if (__put_user(msr, &frame->mc_gregs[PT_MSR]))
- return 1;
+ unsafe_put_user(msr, &frame->mc_gregs[PT_MSR], failed);

if (sigret) {
/* Set up the sigreturn trampoline: li 0,sigret; sc */
- if (__put_user(PPC_INST_ADDI + sigret, &frame->tramp[0])
- || __put_user(PPC_INST_SC, &frame->tramp[1]))
- return 1;
+ unsafe_put_user(PPC_INST_ADDI + sigret, &frame->tramp[0], failed);
+ unsafe_put_user(PPC_INST_SC, &frame->tramp[1], failed);
}
+ user_write_access_end();
+
if (sigret)
flush_icache_range((unsigned long) &frame->tramp[0],
(unsigned long) &frame->tramp[2]);
@@ -341,6 +344,10 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
return 1;

return 0;
+
+failed:
+ user_write_access_end();
+ return 1;
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
@@ -369,15 +376,17 @@ static int save_tm_user_regs(struct pt_regs *regs,
flush_spe_to_thread(current);
#endif

- if (save_general_regs(&current->thread.ckpt_regs, frame))
+ if (!user_write_access_begin(frame, sizeof(*frame)))
return 1;

+ if (save_general_regs(&current->thread.ckpt_regs, frame))
+ goto failed;
+
#ifdef CONFIG_ALTIVEC
/* save altivec registers */
if (current->thread.used_vr) {
- if (__copy_to_user(&frame->mc_vregs, &current->thread.ckvr_state,
- ELF_NVRREG * sizeof(vector128)))
- return 1;
+ unsafe_copy_to_user(&frame->mc_vregs, &current->thread.ckvr_state,
+ ELF_NVRREG * sizeof(vector128), failed);

/* set MSR_VEC in the saved MSR value to indicate that
* frame->mc_vregs contains valid data
@@ -390,13 +399,11 @@ static int save_tm_user_regs(struct pt_regs *regs,
* significant bits of a vector, we "cheat" and stuff VRSAVE in the
* most significant bits of that same vector. --BenH
*/
- if (__put_user(current->thread.ckvrsave,
- (u32 __user *)&frame->mc_vregs[32]))
- return 1;
+ unsafe_put_user(current->thread.ckvrsave,
+ (u32 __user *)&frame->mc_vregs[32], failed);
#endif /* CONFIG_ALTIVEC */

- if (copy_ckfpr_to_user(&frame->mc_fregs, current))
- return 1;
+ unsafe_copy_ckfpr_to_user(&frame->mc_fregs, current, failed);
#ifdef CONFIG_VSX
/*
* Copy VSR 0-31 upper half from thread_struct to local
@@ -405,8 +412,7 @@ static int save_tm_user_regs(struct pt_regs *regs,
* contains valid data
*/
if (current->thread.used_vsr) {
- if (copy_ckvsx_to_user(&frame->mc_vsregs, current))
- return 1;
+ unsafe_copy_ckvsx_to_user(&frame->mc_vsregs, current, failed);
msr |= MSR_VSX;
}
#endif /* CONFIG_VSX */
@@ -415,91 +421,85 @@ static int save_tm_user_regs(struct pt_regs *regs,
* simply the same as in save_user_regs().
*/
if (current->thread.used_spe) {
- if (__copy_to_user(&frame->mc_vregs, current->thread.evr,
- ELF_NEVRREG * sizeof(u32)))
- return 1;
+ unsafe_copy_to_user(&frame->mc_vregs, current->thread.evr,
+ ELF_NEVRREG * sizeof(u32), failed);
/* set MSR_SPE in the saved MSR value to indicate that
* frame->mc_vregs contains valid data */
msr |= MSR_SPE;
}

/* We always copy to/from spefscr */
- if (__put_user(current->thread.spefscr, (u32 __user *)&frame->mc_vregs + ELF_NEVRREG))
- return 1;
+ unsafe_put_user(current->thread.spefscr,
+ (u32 __user *)&frame->mc_vregs + ELF_NEVRREG, failed);
#endif /* CONFIG_SPE */

- if (__put_user(msr, &frame->mc_gregs[PT_MSR]))
- return 1;
+ unsafe_put_user(msr, &frame->mc_gregs[PT_MSR], failed);
+
if (sigret) {
/* Set up the sigreturn trampoline: li 0,sigret; sc */
- if (__put_user(PPC_INST_ADDI + sigret, &frame->tramp[0])
- || __put_user(PPC_INST_SC, &frame->tramp[1]))
- return 1;
+ unsafe_put_user(PPC_INST_ADDI + sigret, &frame->tramp[0], failed);
+ unsafe_put_user(PPC_INST_SC, &frame->tramp[1], failed);
}
+ user_write_access_end();
+
if (sigret)
flush_icache_range((unsigned long) &frame->tramp[0],
(unsigned long) &frame->tramp[2]);

- if (save_general_regs(regs, tm_frame))
+ if (!user_write_access_begin(tm_frame, sizeof(*tm_frame)))
return 1;

+ if (save_general_regs(regs, tm_frame))
+ goto failed;
+
/* Stash the top half of the 64bit MSR into the 32bit MSR word
* of the transactional mcontext. This way we have a backward-compatible
* MSR in the 'normal' (checkpointed) mcontext and additionally one can
* also look at what type of transaction (T or S) was active at the
* time of the signal.
*/
- if (__put_user((msr >> 32), &tm_frame->mc_gregs[PT_MSR]))
- return 1;
+ unsafe_put_user((msr >> 32), &tm_frame->mc_gregs[PT_MSR], failed);

#ifdef CONFIG_ALTIVEC
if (current->thread.used_vr) {
- if (msr & MSR_VEC) {
- if (__copy_to_user(&tm_frame->mc_vregs,
- &current->thread.vr_state,
- ELF_NVRREG * sizeof(vector128)))
- return 1;
- } else {
- if (__copy_to_user(&tm_frame->mc_vregs,
- &current->thread.ckvr_state,
- ELF_NVRREG * sizeof(vector128)))
- return 1;
- }
+ if (msr & MSR_VEC)
+ unsafe_copy_to_user(&tm_frame->mc_vregs,
+ &current->thread.vr_state,
+ ELF_NVRREG * sizeof(vector128), failed);
+ else
+ unsafe_copy_to_user(&tm_frame->mc_vregs,
+ &current->thread.ckvr_state,
+ ELF_NVRREG * sizeof(vector128), failed);
}

- if (msr & MSR_VEC) {
- if (__put_user(current->thread.vrsave,
- (u32 __user *)&tm_frame->mc_vregs[32]))
- return 1;
- } else {
- if (__put_user(current->thread.ckvrsave,
- (u32 __user *)&tm_frame->mc_vregs[32]))
- return 1;
- }
+ if (msr & MSR_VEC)
+ unsafe_put_user(current->thread.vrsave,
+ (u32 __user *)&tm_frame->mc_vregs[32], failed);
+ else
+ unsafe_put_user(current->thread.ckvrsave,
+ (u32 __user *)&tm_frame->mc_vregs[32], failed);
#endif /* CONFIG_ALTIVEC */

- if (msr & MSR_FP) {
- if (copy_fpr_to_user(&tm_frame->mc_fregs, current))
- return 1;
- } else {
- if (copy_ckfpr_to_user(&tm_frame->mc_fregs, current))
- return 1;
- }
+ if (msr & MSR_FP)
+ unsafe_copy_fpr_to_user(&tm_frame->mc_fregs, current, failed);
+ else
+ unsafe_copy_ckfpr_to_user(&tm_frame->mc_fregs, current, failed);

#ifdef CONFIG_VSX
if (current->thread.used_vsr) {
- if (msr & MSR_VSX) {
- if (copy_vsx_to_user(&tm_frame->mc_vsregs,
- current))
- return 1;
- } else {
- if (copy_ckvsx_to_user(&tm_frame->mc_vsregs, current))
- return 1;
- }
+ if (msr & MSR_VSX)
+ unsafe_copy_vsx_to_user(&tm_frame->mc_vsregs, current, failed);
+ else
+ unsafe_copy_ckvsx_to_user(&tm_frame->mc_vsregs, current, failed);
}
#endif /* CONFIG_VSX */

+ user_write_access_end();
return 0;
+
+failed:
+ user_write_access_end();
+ return 1;
}
#endif

--
2.25.0