[PATCH v12 4/8] powerpc/perf: consolidate valid_user_sp -> invalid_user_sp

From: Michal Suchanek
Date: Fri Mar 20 2020 - 06:21:00 EST


Merge the 32bit and 64bit version.

Halve the check constants on 32bit.

Use STACK_TOP since it is defined.

Passing is_64 is now redundant since is_32bit_task() is used to
determine which callchain variant should be used. Use STACK_TOP and
is_32bit_task() directly.

This removes a page from the valid 32bit area on 64bit:
#define TASK_SIZE_USER32 (0x0000000100000000UL - (1 * PAGE_SIZE))
#define STACK_TOP_USER32 TASK_SIZE_USER32

Change return value to bool. It is inverted by users anyway.

Change to invalid_user_sp to avoid inverting the return value twice.

Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
---
v8: new patch
v11: simplify by using is_32bit_task()
v12:
- simplify by precalculating subexpresions
- change return value to bool
- remove double inversion
---
arch/powerpc/perf/callchain.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index c9a78c6e4361..001d0473a61f 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -102,6 +102,14 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
}
}

+static inline bool invalid_user_sp(unsigned long sp)
+{
+ unsigned long mask = is_32bit_task() ? 3 : 7;
+ unsigned long top = STACK_TOP - (is_32bit_task() ? 16 : 32);
+
+ return (!sp || (sp & mask) || (sp > top));
+}
+
#ifdef CONFIG_PPC64
/*
* On 64-bit we don't want to invoke hash_page on user addresses from
@@ -161,13 +169,6 @@ static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
return read_user_stack_slow(ptr, ret, 8);
}

-static inline int valid_user_sp(unsigned long sp, int is_64)
-{
- if (!sp || (sp & 7) || sp > (is_64 ? TASK_SIZE : 0x100000000UL) - 32)
- return 0;
- return 1;
-}
-
/*
* 64-bit user processes use the same stack frame for RT and non-RT signals.
*/
@@ -226,7 +227,7 @@ static void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,

while (entry->nr < entry->max_stack) {
fp = (unsigned long __user *) sp;
- if (!valid_user_sp(sp, 1) || read_user_stack_64(fp, &next_sp))
+ if (invalid_user_sp(sp) || read_user_stack_64(fp, &next_sp))
return;
if (level > 0 && read_user_stack_64(&fp[2], &next_ip))
return;
@@ -275,13 +276,6 @@ static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry
{
}

-static inline int valid_user_sp(unsigned long sp, int is_64)
-{
- if (!sp || (sp & 7) || sp > TASK_SIZE - 32)
- return 0;
- return 1;
-}
-
#define __SIGNAL_FRAMESIZE32 __SIGNAL_FRAMESIZE
#define sigcontext32 sigcontext
#define mcontext32 mcontext
@@ -423,7 +417,7 @@ static void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,

while (entry->nr < entry->max_stack) {
fp = (unsigned int __user *) (unsigned long) sp;
- if (!valid_user_sp(sp, 0) || read_user_stack_32(fp, &next_sp))
+ if (invalid_user_sp(sp) || read_user_stack_32(fp, &next_sp))
return;
if (level > 0 && read_user_stack_32(&fp[1], &next_ip))
return;
--
2.23.0