linux-kernel - [PATCH v8 4/7] powerpc/perf: consolidate valid_user

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Date:   Thu, 12 Sep 2019 19:26:06 +0200
From:   Michal Suchanek <msuchanek@...e.de>
To:     linuxppc-dev@...ts.ozlabs.org
Cc:     Michal Suchanek <msuchanek@...e.de>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Nicholas Piggin <npiggin@...il.com>,
        Christophe Leroy <christophe.leroy@....fr>,
        Breno Leitao <leitao@...ian.org>,
        Arnd Bergmann <arnd@...db.de>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Firoz Khan <firoz.khan@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Joel Stanley <joel@....id.au>,
        Hari Bathini <hbathini@...ux.ibm.com>,
        Michael Neuling <mikey@...ling.org>,
        Andrew Donnellan <andrew.donnellan@....ibm.com>,
        Russell Currey <ruscur@...sell.cc>,
        Diana Craciun <diana.craciun@....com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        David Hildenbrand <david@...hat.com>,
        Allison Randal <allison@...utok.net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH v8 4/7] powerpc/perf: consolidate valid_user_sp

Merge the 32bit and 64bit version.

Halve the check constants on 32bit.

Use STACK_TOP since it is defined.

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@...e.de>
---
v8: new patch
---
 arch/powerpc/perf/callchain.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index d86bdbffda9e..7863ee0a0e69 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -102,6 +102,20 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
 	}
 }
 
+static inline int valid_user_sp(unsigned long sp, int is_64)
+{
+	unsigned long stack_top;
+
+	if (IS_ENABLED(CONFIG_PPC32))
+		stack_top = STACK_TOP;
+	else    /* STACK_TOP uses is_32bit_task() but we want is_64 */
+		stack_top = is_64 ? STACK_TOP_USER64 : STACK_TOP_USER32;
+
+	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
@@ -165,13 +179,6 @@ 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.
  */
@@ -294,13 +301,6 @@ static inline int current_is_64bit(void)
 	return 0;
 }
 
-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
-- 
2.23.0