powerpc/signal32: Convert restore_[tm]_user_regs() to user access block

Convert restore_user_regs() and restore_tm_user_regs()
to use user_access_read_begin/end blocks.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/181adf15a6f644efcd1aeafb355f3578ff1b6bc5.1616151715.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index f10498e1b3f6176e001287f46d86edb94d3db9dc..95600f3a6523a5c9c3561e0eba655e9c53621106 100644 (file)
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -245,7 +245,7 @@ static inline bool trap_norestart(struct pt_regs *regs)
        return regs->trap & 0x10;
 }
 
-static inline void set_trap_norestart(struct pt_regs *regs)
+static __always_inline void set_trap_norestart(struct pt_regs *regs)
 {
        regs->trap |= 0x10;
 }

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 088c838530266f595c9cbad78d6aff9e366a5c6f..0b1a6f53e5539452eeb1561a77de3f9d83e28352 100644 (file)
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -116,8 +116,8 @@ failed:
        return 1;
 }
 
-static inline int restore_general_regs(struct pt_regs *regs,
-               struct mcontext __user *sr)
+static __always_inline int
+__unsafe_restore_general_regs(struct pt_regs *regs, struct mcontext __user *sr)
 {
        elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
        int i;
@@ -125,10 +125,12 @@ static inline int restore_general_regs(struct pt_regs *regs,
        for (i = 0; i <= PT_RESULT; i++) {
                if ((i == PT_MSR) || (i == PT_SOFTE))
                        continue;
-               if (__get_user(gregs[i], &sr->mc_gregs[i]))
-                       return -EFAULT;
+               unsafe_get_user(gregs[i], &sr->mc_gregs[i], failed);
        }
        return 0;
+
+failed:
+       return 1;
 }
 
 #else /* CONFIG_PPC64 */
@@ -161,18 +163,20 @@ failed:
        return 1;
 }
 
-static inline int restore_general_regs(struct pt_regs *regs,
-               struct mcontext __user *sr)
+static __always_inline
+int __unsafe_restore_general_regs(struct pt_regs *regs, struct mcontext __user *sr)
 {
        /* copy up to but not including MSR */
-       if (__copy_from_user(regs, &sr->mc_gregs,
-                               PT_MSR * sizeof(elf_greg_t)))
-               return -EFAULT;
+       unsafe_copy_from_user(regs, &sr->mc_gregs, PT_MSR * sizeof(elf_greg_t), failed);
+
        /* copy from orig_r3 (the word after the MSR) up to the end */
-       if (__copy_from_user(&regs->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
-                               GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t)))
-               return -EFAULT;
+       unsafe_copy_from_user(&regs->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
+                             GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t), failed);
+
        return 0;
+
+failed:
+       return 1;
 }
 #endif
 
@@ -181,6 +185,11 @@ static inline int restore_general_regs(struct pt_regs *regs,
                goto label;                                     \
 } while (0)
 
+#define unsafe_restore_general_regs(regs, frame, label) do {   \
+       if (__unsafe_restore_general_regs(regs, frame))         \
+               goto label;                                     \
+} while (0)
+
 /*
  * When we have signals to deliver, we set up on the
  * user stack, going down from the original stack pointer:
@@ -485,14 +494,13 @@ static int save_tm_user_regs_unsafe(struct pt_regs *regs, struct mcontext __user
 static long restore_user_regs(struct pt_regs *regs,
                              struct mcontext __user *sr, int sig)
 {
-       long err;
        unsigned int save_r2 = 0;
        unsigned long msr;
 #ifdef CONFIG_VSX
        int i;
 #endif
 
-       if (!access_ok(sr, sizeof(*sr)))
+       if (!user_read_access_begin(sr, sizeof(*sr)))
                return 1;
        /*
         * restore general registers but not including MSR or SOFTE. Also
@@ -500,13 +508,11 @@ static long restore_user_regs(struct pt_regs *regs,
         */
        if (!sig)
                save_r2 = (unsigned int)regs->gpr[2];
-       err = restore_general_regs(regs, sr);
+       unsafe_restore_general_regs(regs, sr, failed);
        set_trap_norestart(regs);
-       err |= __get_user(msr, &sr->mc_gregs[PT_MSR]);
+       unsafe_get_user(msr, &sr->mc_gregs[PT_MSR], failed);
        if (!sig)
                regs->gpr[2] = (unsigned long) save_r2;
-       if (err)
-               return 1;
 
        /* if doing signal return, restore the previous little-endian mode */
        if (sig)
@@ -520,22 +526,19 @@ static long restore_user_regs(struct pt_regs *regs,
        regs->msr &= ~MSR_VEC;
        if (msr & MSR_VEC) {
                /* restore altivec registers from the stack */
-               if (__copy_from_user(&current->thread.vr_state, &sr->mc_vregs,
-                                    sizeof(sr->mc_vregs)))
-                       return 1;
+               unsafe_copy_from_user(&current->thread.vr_state, &sr->mc_vregs,
+                                     sizeof(sr->mc_vregs), failed);
                current->thread.used_vr = true;
        } else if (current->thread.used_vr)
                memset(&current->thread.vr_state, 0,
                       ELF_NVRREG * sizeof(vector128));
 
        /* Always get VRSAVE back */
-       if (__get_user(current->thread.vrsave, (u32 __user *)&sr->mc_vregs[32]))
-               return 1;
+       unsafe_get_user(current->thread.vrsave, (u32 __user *)&sr->mc_vregs[32], failed);
        if (cpu_has_feature(CPU_FTR_ALTIVEC))
                mtspr(SPRN_VRSAVE, current->thread.vrsave);
 #endif /* CONFIG_ALTIVEC */
-       if (copy_fpr_from_user(current, &sr->mc_fregs))
-               return 1;
+       unsafe_copy_fpr_from_user(current, &sr->mc_fregs, failed);
 
 #ifdef CONFIG_VSX
        /*
@@ -548,8 +551,7 @@ static long restore_user_regs(struct pt_regs *regs,
                 * Restore altivec registers from the stack to a local
                 * buffer, then write this out to the thread_struct
                 */
-               if (copy_vsx_from_user(current, &sr->mc_vsregs))
-                       return 1;
+               unsafe_copy_vsx_from_user(current, &sr->mc_vsregs, failed);
                current->thread.used_vsr = true;
        } else if (current->thread.used_vsr)
                for (i = 0; i < 32 ; i++)
@@ -567,19 +569,22 @@ static long restore_user_regs(struct pt_regs *regs,
        regs->msr &= ~MSR_SPE;
        if (msr & MSR_SPE) {
                /* restore spe registers from the stack */
-               if (__copy_from_user(current->thread.evr, &sr->mc_vregs,
-                                    ELF_NEVRREG * sizeof(u32)))
-                       return 1;
+               unsafe_copy_from_user(current->thread.evr, &sr->mc_vregs,
+                                     ELF_NEVRREG * sizeof(u32));
                current->thread.used_spe = true;
        } else if (current->thread.used_spe)
                memset(current->thread.evr, 0, ELF_NEVRREG * sizeof(u32));
 
        /* Always get SPEFSCR back */
-       if (__get_user(current->thread.spefscr, (u32 __user *)&sr->mc_vregs + ELF_NEVRREG))
-               return 1;
+       unsafe_get_user(current->thread.spefscr, (u32 __user *)&sr->mc_vregs + ELF_NEVRREG, failed);
 #endif /* CONFIG_SPE */
 
+       user_read_access_end();
        return 0;
+
+failed:
+       user_read_access_end();
+       return 1;
 }
 
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
@@ -592,7 +597,6 @@ static long restore_tm_user_regs(struct pt_regs *regs,
                                 struct mcontext __user *sr,
                                 struct mcontext __user *tm_sr)
 {
-       long err;
        unsigned long msr, msr_hi;
 #ifdef CONFIG_VSX
        int i;
@@ -607,14 +611,13 @@ static long restore_tm_user_regs(struct pt_regs *regs,
         * TFHAR is restored from the checkpointed NIP; TEXASR and TFIAR
         * were set by the signal delivery.
         */
-       err = restore_general_regs(&current->thread.ckpt_regs, sr);
-
-       err |= __get_user(current->thread.tm_tfhar, &sr->mc_gregs[PT_NIP]);
-
-       err |= __get_user(msr, &sr->mc_gregs[PT_MSR]);
-       if (err)
+       if (!user_read_access_begin(sr, sizeof(*sr)))
                return 1;
 
+       unsafe_restore_general_regs(&current->thread.ckpt_regs, sr, failed);
+       unsafe_get_user(current->thread.tm_tfhar, &sr->mc_gregs[PT_NIP], failed);
+       unsafe_get_user(msr, &sr->mc_gregs[PT_MSR], failed);
+
        /* Restore the previous little-endian mode */
        regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 
@@ -622,9 +625,8 @@ static long restore_tm_user_regs(struct pt_regs *regs,
        regs->msr &= ~MSR_VEC;
        if (msr & MSR_VEC) {
                /* restore altivec registers from the stack */
-               if (__copy_from_user(&current->thread.ckvr_state, &sr->mc_vregs,
-                                    sizeof(sr->mc_vregs)))
-                       return 1;
+               unsafe_copy_from_user(&current->thread.ckvr_state, &sr->mc_vregs,
+                                     sizeof(sr->mc_vregs), failed);
                current->thread.used_vr = true;
        } else if (current->thread.used_vr) {
                memset(&current->thread.vr_state, 0,
@@ -634,17 +636,15 @@ static long restore_tm_user_regs(struct pt_regs *regs,
        }
 
        /* Always get VRSAVE back */
-       if (__get_user(current->thread.ckvrsave,
-                      (u32 __user *)&sr->mc_vregs[32]))
-               return 1;
+       unsafe_get_user(current->thread.ckvrsave,
+                       (u32 __user *)&sr->mc_vregs[32], failed);
        if (cpu_has_feature(CPU_FTR_ALTIVEC))
                mtspr(SPRN_VRSAVE, current->thread.ckvrsave);
 #endif /* CONFIG_ALTIVEC */
 
        regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);
 
-       if (copy_fpr_from_user(current, &sr->mc_fregs))
-               return 1;
+       unsafe_copy_fpr_from_user(current, &sr->mc_fregs, failed);
 
 #ifdef CONFIG_VSX
        regs->msr &= ~MSR_VSX;
@@ -653,8 +653,7 @@ static long restore_tm_user_regs(struct pt_regs *regs,
                 * Restore altivec registers from the stack to a local
                 * buffer, then write this out to the thread_struct
                 */
-               if (copy_ckvsx_from_user(current, &sr->mc_vsregs))
-                       return 1;
+               unsafe_copy_ckvsx_from_user(current, &sr->mc_vsregs, failed);
                current->thread.used_vsr = true;
        } else if (current->thread.used_vsr)
                for (i = 0; i < 32 ; i++) {
@@ -669,39 +668,36 @@ static long restore_tm_user_regs(struct pt_regs *regs,
         */
        regs->msr &= ~MSR_SPE;
        if (msr & MSR_SPE) {
-               if (__copy_from_user(current->thread.evr, &sr->mc_vregs,
-                                    ELF_NEVRREG * sizeof(u32)))
-                       return 1;
+               unsafe_copy_from_user(current->thread.evr, &sr->mc_vregs,
+                                     ELF_NEVRREG * sizeof(u32), failed);
                current->thread.used_spe = true;
        } else if (current->thread.used_spe)
                memset(current->thread.evr, 0, ELF_NEVRREG * sizeof(u32));
 
        /* Always get SPEFSCR back */
-       if (__get_user(current->thread.spefscr, (u32 __user *)&sr->mc_vregs
-                      + ELF_NEVRREG))
-               return 1;
+       unsafe_get_user(current->thread.spefscr,
+                       (u32 __user *)&sr->mc_vregs + ELF_NEVRREG, failed);
 #endif /* CONFIG_SPE */
 
-       err = restore_general_regs(regs, tm_sr);
-       if (err)
+       user_read_access_end();
+
+       if (!user_read_access_begin(tm_sr, sizeof(*tm_sr)))
                return 1;
 
+       unsafe_restore_general_regs(regs, tm_sr, failed);
+
 #ifdef CONFIG_ALTIVEC
        /* restore altivec registers from the stack */
        if (msr & MSR_VEC)
-               if (__copy_from_user(&current->thread.vr_state,
-                                    &tm_sr->mc_vregs,
-                                    sizeof(sr->mc_vregs)))
-                       return 1;
+               unsafe_copy_from_user(&current->thread.vr_state, &tm_sr->mc_vregs,
+                                     sizeof(sr->mc_vregs), failed);
 
        /* Always get VRSAVE back */
-       if (__get_user(current->thread.vrsave,
-                      (u32 __user *)&tm_sr->mc_vregs[32]))
-               return 1;
+       unsafe_get_user(current->thread.vrsave,
+                       (u32 __user *)&tm_sr->mc_vregs[32], failed);
 #endif /* CONFIG_ALTIVEC */
 
-       if (copy_ckfpr_from_user(current, &tm_sr->mc_fregs))
-               return 1;
+       unsafe_copy_ckfpr_from_user(current, &tm_sr->mc_fregs, failed);
 
 #ifdef CONFIG_VSX
        if (msr & MSR_VSX) {
@@ -709,16 +705,17 @@ static long restore_tm_user_regs(struct pt_regs *regs,
                 * Restore altivec registers from the stack to a local
                 * buffer, then write this out to the thread_struct
                 */
-               if (copy_vsx_from_user(current, &tm_sr->mc_vsregs))
-                       return 1;
+               unsafe_copy_vsx_from_user(current, &tm_sr->mc_vsregs, failed);
                current->thread.used_vsr = true;
        }
 #endif /* CONFIG_VSX */
 
        /* Get the top half of the MSR from the user context */
-       if (__get_user(msr_hi, &tm_sr->mc_gregs[PT_MSR]))
-               return 1;
+       unsafe_get_user(msr_hi, &tm_sr->mc_gregs[PT_MSR], failed);
        msr_hi <<= 32;
+
+       user_read_access_end();
+
        /* If TM bits are set to the reserved value, it's an invalid context */
        if (MSR_TM_RESV(msr_hi))
                return 1;
@@ -766,6 +763,10 @@ static long restore_tm_user_regs(struct pt_regs *regs,
        preempt_enable();
 
        return 0;
+
+failed:
+       user_read_access_end();
+       return 1;
 }
 #else
 static long restore_tm_user_regs(struct pt_regs *regs, struct mcontext __user *sr,