On Tue, Apr 7, 2020 at 8:48 PM Balamuruhan S [off-list ref] wrote:

On Mon, 2020-04-06 at 18:09 +1000, Jordan Niethe wrote:

quoted

Define specific __get_user_instr() and __get_user_instr_inatomic()
macros for reading instructions from user space.

Signed-off-by: Jordan Niethe <redacted>
---
 arch/powerpc/include/asm/uaccess.h  | 5 +++++
 arch/powerpc/kernel/align.c         | 2 +-
 arch/powerpc/kernel/hw_breakpoint.c | 2 +-
 arch/powerpc/kernel/vecemu.c        | 2 +-
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/uaccess.h

b/arch/powerpc/include/asm/uaccess.h
index 2f500debae21..c0a35e4586a5 100644

--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h

@@ -105,6 +105,11 @@ static inline int __access_ok(unsigned long addr,

unsigned long size,
 #define __put_user_inatomic(x, ptr) \
      __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

+#define __get_user_instr(x, ptr) \
+     __get_user_nocheck((x).val, (u32 *)(ptr), sizeof(u32), true)
+
+#define __get_user_instr_inatomic(x, ptr) \
+     __get_user_nosleep((x).val, (u32 *)(ptr), sizeof(u32))

should we use ppc_inst_val() ?

The __get_user() macros load a value into the given variable, so we
can not use ppc_inst_val().

-- Bala

quoted

 extern long __put_user_bad(void);

 /*

diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index 66a6d1de7799..65cdfd41e3a1 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c

@@ -304,7 +304,7 @@ int fix_alignment(struct pt_regs *regs)
       */
      CHECK_FULL_REGS(regs);

-     if (unlikely(__get_user(instr.val, (unsigned int __user *)regs->nip)))
+     if (unlikely(__get_user_instr(instr, (void __user *)regs->nip)))
              return -EFAULT;
      if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
              /* We don't handle PPC little-endian any more... */

diff --git a/arch/powerpc/kernel/hw_breakpoint.c

b/arch/powerpc/kernel/hw_breakpoint.c
index 542f65ccf68b..cebab14e2788 100644

--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c

@@ -249,7 +249,7 @@ static bool stepping_handler(struct pt_regs *regs, struct

perf_event *bp,
      struct instruction_op op;
      unsigned long addr = info->address;

-     if (__get_user_inatomic(instr.val, (unsigned int *)regs->nip))
+     if (__get_user_instr_inatomic(instr, (void __user *)regs->nip))
              goto fail;

      ret = analyse_instr(&op, regs, instr);

diff --git a/arch/powerpc/kernel/vecemu.c b/arch/powerpc/kernel/vecemu.c
index bbf536e10902..c82ede46d71b 100644
--- a/arch/powerpc/kernel/vecemu.c
+++ b/arch/powerpc/kernel/vecemu.c

@@ -266,7 +266,7 @@ int emulate_altivec(struct pt_regs *regs)
      unsigned int va, vb, vc, vd;
      vector128 *vrs;

-     if (get_user(instr.val, (unsigned int __user *) regs->nip))
+     if (__get_user_instr(instr, (void __user *) regs->nip))
              return -EFAULT;

      word = ppc_inst_val(instr);