All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] ARM: vfp: Fix up exception location in Thumb mode
@ 2011-01-14  7:42 ` Colin Cross
  0 siblings, 0 replies; 64+ messages in thread
From: Colin Cross @ 2011-01-14  7:42 UTC (permalink / raw)
  To: linux-arm-kernel; +Cc: Catalin Marinas, Colin Cross, Russell King, linux-kernel

The exception handler in entry-armv.S checks for thumb mode and
correctly determines the exception location and instruction,
but VFP_bounce uses the uncorrected location off the stack.
If the VFP exception occured in Thumb mode, fix up the
exception location to match the value that would be returned
in ARM mode.

Fixes segfaults in userspace applications running in Thumb mode
caused by a handled VFP exception returning to the middle of the
instruction that triggered the exception.

Change-Id: I6c6ba1ab88e107bec166ea334d7e0974a4f6bfba
Signed-off-by: Colin Cross <ccross@android.com>
---
 arch/arm/vfp/vfpmodule.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 0797cb5..63ed73d 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -275,6 +275,16 @@ void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
 	pr_debug("VFP: bounce: trigger %08x fpexc %08x\n", trigger, fpexc);
 
 	/*
+	 * If the exception occured in thumb mode, pc is exception location + 2,
+	 * the middle of the 32-bit VFP instruction.  Add 2 to get exception
+	 * location + 4, the same we get in ARM mode.
+	 */
+#ifdef CONFIG_ARM_THUMB
+	if (regs->ARM_cpsr & PSR_T_BIT)
+		regs->ARM_pc += 2;
+#endif
+
+	/*
 	 * At this point, FPEXC can have the following configuration:
 	 *
 	 *  EX DEX IXE
-- 
1.7.3.1


^ permalink raw reply related	[flat|nested] 64+ messages in thread

end of thread, other threads:[~2011-02-09 18:12 UTC | newest]

Thread overview: 64+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-01-14  7:42 [PATCH] ARM: vfp: Fix up exception location in Thumb mode Colin Cross
2011-01-14  7:42 ` Colin Cross
2011-01-14 11:43 ` Catalin Marinas
2011-01-14 11:43   ` Catalin Marinas
2011-01-14 12:02   ` Russell King - ARM Linux
2011-01-14 12:02     ` Russell King - ARM Linux
2011-01-14 14:10     ` Catalin Marinas
2011-01-14 14:10       ` Catalin Marinas
2011-01-14 15:49       ` Russell King - ARM Linux
2011-01-14 15:49         ` Russell King - ARM Linux
2011-01-14 16:23         ` Catalin Marinas
2011-01-14 16:23           ` Catalin Marinas
2011-01-14 16:35           ` Russell King - ARM Linux
2011-01-14 16:35             ` Russell King - ARM Linux
2011-01-14 16:58             ` Catalin Marinas
2011-01-14 16:58               ` Catalin Marinas
2011-01-14 17:30               ` Russell King - ARM Linux
2011-01-14 17:30                 ` Russell King - ARM Linux
2011-01-14 18:47                 ` Russell King - ARM Linux
2011-01-14 18:47                   ` Russell King - ARM Linux
2011-01-14 19:23                   ` Colin Cross
2011-01-14 19:23                     ` Colin Cross
2011-01-14 19:51                     ` Colin Cross
2011-01-14 19:51                       ` Colin Cross
2011-01-14 21:24                       ` Russell King - ARM Linux
2011-01-14 21:24                         ` Russell King - ARM Linux
2011-01-25 23:33                       ` Colin Cross
2011-01-25 23:33                         ` Colin Cross
2011-01-26 11:26                         ` Russell King - ARM Linux
2011-01-26 11:26                           ` Russell King - ARM Linux
2011-01-27  6:11                           ` Colin Cross
2011-01-27  6:11                             ` Colin Cross
2011-01-27  6:35                             ` Colin Cross
2011-01-27  6:35                               ` Colin Cross
2011-01-27  7:30                               ` Colin Cross
2011-01-27  7:30                                 ` Colin Cross
2011-02-09 18:12                                 ` Colin Cross
2011-02-09 18:12                                   ` Colin Cross
2011-01-15 15:38                   ` Catalin Marinas
2011-01-15 15:38                     ` Catalin Marinas
2011-01-15 15:43                     ` Russell King - ARM Linux
2011-01-15 15:43                       ` Russell King - ARM Linux
2011-01-16 11:51                       ` Catalin Marinas
2011-01-16 11:51                         ` Catalin Marinas
2011-01-15 15:31                 ` Catalin Marinas
2011-01-15 15:31                   ` Catalin Marinas
2011-01-15 15:40                   ` Russell King - ARM Linux
2011-01-15 15:40                     ` Russell King - ARM Linux
2011-01-16 11:49                     ` Catalin Marinas
2011-01-16 11:49                       ` Catalin Marinas
2011-01-23 15:51                       ` Russell King - ARM Linux
2011-01-23 15:51                         ` Russell King - ARM Linux
2011-01-25 13:19                         ` Catalin Marinas
2011-01-25 13:19                           ` Catalin Marinas
2011-01-16 21:25                     ` Catalin Marinas
2011-01-16 21:25                       ` Catalin Marinas
2011-01-23 15:46                       ` Russell King - ARM Linux
2011-01-23 15:46                         ` Russell King - ARM Linux
2011-01-25 13:45                         ` Catalin Marinas
2011-01-25 13:45                           ` Catalin Marinas
2011-01-14 16:24       ` Dave Martin
2011-01-14 16:24         ` Dave Martin
2011-01-14 16:52         ` Russell King - ARM Linux
2011-01-14 16:52           ` Russell King - ARM Linux

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.