[PATCH 2/2] powerpc: use probe_user_read() and probe_user_address()

Christophe Leroy
2018-12-03T17:06:47Z

Instead of opencoding, use probe_user_read() and probe_user_address()
to failessly read a user location.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/process.c | 12 +-----------
arch/powerpc/mm/fault.c | 6 +-----
arch/powerpc/perf/callchain.c | 20 +++-----------------
arch/powerpc/perf/core-book3s.c | 8 +-------
arch/powerpc/sysdev/fsl_pci.c | 9 +++------
5 files changed, 9 insertions(+), 46 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 96f34730010f..b77a2b4007e5 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1298,16 +1298,6 @@ void show_user_instructions(struct pt_regs *regs)

pc = regs->nip - (NR_INSN_TO_PRINT * 3 / 4 * sizeof(int));

- /*
- * Make sure the NIP points at userspace, not kernel text/data or
- * elsewhere.
- */
- if (!__access_ok(pc, NR_INSN_TO_PRINT * sizeof(int), USER_DS)) {
- pr_info("%s[%d]: Bad NIP, not dumping instructions.\n",
- current->comm, current->pid);
- return;
- }
-
seq_buf_init(&s, buf, sizeof(buf));

while (n) {
@@ -1318,7 +1308,7 @@ void show_user_instructions(struct pt_regs *regs)
for (i = 0; i < 8 && n; i++, n--, pc += sizeof(int)) {
int instr;

- if (probe_kernel_address((const void *)pc, instr)) {
+ if (probe_user_address((const void *)pc, instr)) {
seq_buf_printf(&s, "XXXXXXXX ");
continue;
}
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 1697e903bbf2..a87a2d2e7a8b 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -274,12 +274,8 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address,
if ((flags & FAULT_FLAG_WRITE) && (flags & FAULT_FLAG_USER) &&
access_ok(VERIFY_READ, nip, sizeof(*nip))) {
unsigned int inst;
- int res;

- pagefault_disable();
- res = __get_user_inatomic(inst, nip);
- pagefault_enable();
- if (!res)
+ if (!probe_user_address(nip, inst))
return !store_updates_sp(inst);
*must_retry = true;
}
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index 0af051a1974e..efe518c4e8c7 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -159,12 +159,8 @@ static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
((unsigned long)ptr & 7))
return -EFAULT;

- pagefault_disable();
- if (!__get_user_inatomic(*ret, ptr)) {
- pagefault_enable();
+ if (!probe_user_address(ptr, *ret))
return 0;
- }
- pagefault_enable();

return read_user_stack_slow(ptr, ret, 8);
}
@@ -175,12 +171,8 @@ static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
((unsigned long)ptr & 3))
return -EFAULT;

- pagefault_disable();
- if (!__get_user_inatomic(*ret, ptr)) {
- pagefault_enable();
+ if (!probe_user_address(ptr, *ret))
return 0;
- }
- pagefault_enable();

return read_user_stack_slow(ptr, ret, 4);
}
@@ -307,17 +299,11 @@ static inline int current_is_64bit(void)
*/
static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
{
- int rc;
-
if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
((unsigned long)ptr & 3))
return -EFAULT;

- pagefault_disable();
- rc = __get_user_inatomic(*ret, ptr);
- pagefault_enable();
-
- return rc;
+ return probe_user_address(ptr, *ret);
}

static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 81f8a0c838ae..25b28aa499b9 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -407,7 +407,6 @@ static void power_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
static __u64 power_pmu_bhrb_to(u64 addr)
{
unsigned int instr;
- int ret;
__u64 target;

if (is_kernel_addr(addr)) {
@@ -418,13 +417,8 @@ static __u64 power_pmu_bhrb_to(u64 addr)
}

/* Userspace: need copy instruction here then translate it */
- pagefault_disable();
- ret = __get_user_inatomic(instr, (unsigned int __user *)addr);
- if (ret) {
- pagefault_enable();
+ if (probe_user_address((unsigned int __user *)addr, instr))
return 0;
- }
- pagefault_enable();

target = branch_target(&instr);
if ((!target) || (instr & BRANCH_ABSOLUTE))
diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 918be816b097..b8e2349910b7 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c
@@ -1068,13 +1068,10 @@ int fsl_pci_mcheck_exception(struct pt_regs *regs)
addr += mfspr(SPRN_MCAR);

if (is_in_pci_mem_space(addr)) {
- if (user_mode(regs)) {
- pagefault_disable();
- ret = get_user(inst, (__u32 __user *)regs->nip);
- pagefault_enable();
- } else {
+ if (user_mode(regs))
+ ret = probe_user_address((void *)regs->nip, inst);
+ else
ret = probe_kernel_address((void *)regs->nip, inst);
- }

if (!ret && mcheck_handle_load(regs, inst)) {
regs->nip += 4;
--
2.13.3