From cb1bf2f321b45a06447133b3db00621b7300c456 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Mon, 2 Nov 2015 12:39:28 -0500
Subject: properly access mcontext_t program counter in cancellation handler

using the actual mcontext_t definition rather than an overlaid pointer
array both improves correctness/readability and eliminates some ugly
hacks for archs with 64-bit registers bit 32-bit program counter.

also fix UB due to comparison of pointers not in a common array
object.
---
 arch/aarch64/pthread_arch.h    | 2 +-
 arch/arm/pthread_arch.h        | 2 +-
 arch/i386/pthread_arch.h       | 2 +-
 arch/microblaze/pthread_arch.h | 2 +-
 arch/mips/pthread_arch.h       | 2 +-
 arch/or1k/pthread_arch.h       | 3 +--
 arch/powerpc/pthread_arch.h    | 3 +--
 arch/sh/pthread_arch.h         | 2 +-
 arch/x32/pthread_arch.h        | 2 +-
 arch/x86_64/pthread_arch.h     | 2 +-
 10 files changed, 10 insertions(+), 12 deletions(-)

(limited to 'arch')

diff --git a/arch/aarch64/pthread_arch.h b/arch/aarch64/pthread_arch.h
index 74276f4c..b2e2d8f1 100644
--- a/arch/aarch64/pthread_arch.h
+++ b/arch/aarch64/pthread_arch.h
@@ -8,4 +8,4 @@ static inline struct pthread *__pthread_self()
 #define TLS_ABOVE_TP
 #define TP_ADJ(p) ((char *)(p) + sizeof(struct pthread) - 16)
 
-#define CANCEL_REG_IP 33
+#define MC_PC pc
diff --git a/arch/arm/pthread_arch.h b/arch/arm/pthread_arch.h
index 4a4dd09e..8b8a7fb6 100644
--- a/arch/arm/pthread_arch.h
+++ b/arch/arm/pthread_arch.h
@@ -27,4 +27,4 @@ static inline pthread_t __pthread_self()
 #define TLS_ABOVE_TP
 #define TP_ADJ(p) ((char *)(p) + sizeof(struct pthread) - 8)
 
-#define CANCEL_REG_IP 18
+#define MC_PC arm_pc
diff --git a/arch/i386/pthread_arch.h b/arch/i386/pthread_arch.h
index 1c06c764..7f38a562 100644
--- a/arch/i386/pthread_arch.h
+++ b/arch/i386/pthread_arch.h
@@ -7,4 +7,4 @@ static inline struct pthread *__pthread_self()
 
 #define TP_ADJ(p) (p)
 
-#define CANCEL_REG_IP 14
+#define MC_PC gregs[REG_EIP]
diff --git a/arch/microblaze/pthread_arch.h b/arch/microblaze/pthread_arch.h
index 259d3d61..08d1ba7d 100644
--- a/arch/microblaze/pthread_arch.h
+++ b/arch/microblaze/pthread_arch.h
@@ -7,4 +7,4 @@ static inline struct pthread *__pthread_self()
 
 #define TP_ADJ(p) (p)
 
-#define CANCEL_REG_IP 32
+#define MC_PC regs.pc
diff --git a/arch/mips/pthread_arch.h b/arch/mips/pthread_arch.h
index 93edbd4e..8a499654 100644
--- a/arch/mips/pthread_arch.h
+++ b/arch/mips/pthread_arch.h
@@ -16,4 +16,4 @@ static inline struct pthread *__pthread_self()
 
 #define DTP_OFFSET 0x8000
 
-#define CANCEL_REG_IP (3-(union {int __i; char __b;}){1}.__b)
+#define MC_PC pc
diff --git a/arch/or1k/pthread_arch.h b/arch/or1k/pthread_arch.h
index ad631694..7decd769 100644
--- a/arch/or1k/pthread_arch.h
+++ b/arch/or1k/pthread_arch.h
@@ -14,5 +14,4 @@ static inline struct pthread *__pthread_self()
 #define TLS_ABOVE_TP
 #define TP_ADJ(p) ((char *)(p) + sizeof(struct pthread))
 
-/* word-offset to 'pc' in mcontext_t */
-#define CANCEL_REG_IP 32
+#define MC_PC regs.pc
diff --git a/arch/powerpc/pthread_arch.h b/arch/powerpc/pthread_arch.h
index bb7405d1..7c5c4fad 100644
--- a/arch/powerpc/pthread_arch.h
+++ b/arch/powerpc/pthread_arch.h
@@ -15,9 +15,8 @@ static inline struct pthread *__pthread_self()
 
 #define DTP_OFFSET 0x8000
 
-// offset of the PC register in mcontext_t, divided by the system wordsize
 // the kernel calls the ip "nip", it's the first saved value after the 32
 // GPRs.
-#define CANCEL_REG_IP 32
+#define MC_PC gregs[32]
 
 #define CANARY canary_at_end
diff --git a/arch/sh/pthread_arch.h b/arch/sh/pthread_arch.h
index 65c389ff..2756e7ec 100644
--- a/arch/sh/pthread_arch.h
+++ b/arch/sh/pthread_arch.h
@@ -8,4 +8,4 @@ static inline struct pthread *__pthread_self()
 #define TLS_ABOVE_TP
 #define TP_ADJ(p) ((char *)(p) + sizeof(struct pthread) - 8)
 
-#define CANCEL_REG_IP 17
+#define MC_PC sc_pc
diff --git a/arch/x32/pthread_arch.h b/arch/x32/pthread_arch.h
index 033bfd69..ecb0bbfb 100644
--- a/arch/x32/pthread_arch.h
+++ b/arch/x32/pthread_arch.h
@@ -7,6 +7,6 @@ static inline struct pthread *__pthread_self()
 
 #define TP_ADJ(p) (p)
 
-#define CANCEL_REG_IP 32
+#define MC_PC gregs[REG_RIP]
 
 #define CANARY canary2
diff --git a/arch/x86_64/pthread_arch.h b/arch/x86_64/pthread_arch.h
index 29e4590c..c61509cf 100644
--- a/arch/x86_64/pthread_arch.h
+++ b/arch/x86_64/pthread_arch.h
@@ -7,4 +7,4 @@ static inline struct pthread *__pthread_self()
 
 #define TP_ADJ(p) (p)
 
-#define CANCEL_REG_IP 16
+#define MC_PC gregs[REG_RIP]
-- 
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