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From:   Michal Suchanek <msuchanek@suse.de>
To:     linuxppc-dev@lists.ozlabs.org
Cc:     Michal Suchanek <msuchanek@suse.de>,
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Subject: [PATCH v11 4/8] powerpc/perf: consolidate valid_user_sp
Date:   Thu, 19 Mar 2020 12:52:24 +0100
Message-Id: <1b612025371bb9f2bcce72c700c809ae29e57392.1584613649.git.msuchanek@suse.de>
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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

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
v8: new patch
v11: simplify by using is_32bit_task()
---
 arch/powerpc/perf/callchain.c | 27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index c9a78c6e4361..194c7fd933e6 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -102,6 +102,15 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
 	}
 }
 
+static inline int valid_user_sp(unsigned long sp)
+{
+	bool is_64 = !is_32bit_task();
+
+	if (!sp || (sp & (is_64 ? 7 : 3)) || sp > STACK_TOP - (is_64 ? 32 : 16))
+		return 0;
+	return 1;
+}
+
 #ifdef CONFIG_PPC64
 /*
  * On 64-bit we don't want to invoke hash_page on user addresses from
@@ -161,13 +170,6 @@ 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 +228,7 @@ 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 (!valid_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 +277,6 @@ 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 +418,7 @@ 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 (!valid_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