lkml.org 
[lkml]   [2019]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.3 040/140] ARM: 8914/1: NOMMU: Fix exc_ret for XIP
Date
From: Vladimir Murzin <vladimir.murzin@arm.com>

[ Upstream commit 4c0742f65b4ee466546fd24b71b56516cacd4613 ]

It was reported that 72cd4064fcca "NOMMU: Toggle only bits in
EXC_RETURN we are really care of" breaks NOMMU+XIP combination.
It happens because saved EXC_RETURN gets overwritten when data
section is relocated.

The fix is to propagate EXC_RETURN via register and let relocation
code to commit that value into memory.

Fixes: 72cd4064fcca ("ARM: 8830/1: NOMMU: Toggle only bits in EXC_RETURN we are really care of")
Reported-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Tested-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/kernel/head-common.S | 5 +++--
arch/arm/kernel/head-nommu.S | 2 ++
arch/arm/mm/proc-v7m.S | 5 ++---
3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
index a7810be07da1c..4a3982812a401 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S
@@ -68,7 +68,7 @@ ENDPROC(__vet_atags)
* The following fragment of code is executed with the MMU on in MMU mode,
* and uses absolute addresses; this is not position independent.
*
- * r0 = cp#15 control register
+ * r0 = cp#15 control register (exc_ret for M-class)
* r1 = machine ID
* r2 = atags/dtb pointer
* r9 = processor ID
@@ -137,7 +137,8 @@ __mmap_switched_data:
#ifdef CONFIG_CPU_CP15
.long cr_alignment @ r3
#else
- .long 0 @ r3
+M_CLASS(.long exc_ret) @ r3
+AR_CLASS(.long 0) @ r3
#endif
.size __mmap_switched_data, . - __mmap_switched_data

diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index afa350f44dea3..0fc814bbc34b1 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -201,6 +201,8 @@ M_CLASS(streq r3, [r12, #PMSAv8_MAIR1])
bic r0, r0, #V7M_SCB_CCR_IC
#endif
str r0, [r12, V7M_SCB_CCR]
+ /* Pass exc_ret to __mmap_switched */
+ mov r0, r10
#endif /* CONFIG_CPU_CP15 elif CONFIG_CPU_V7M */
ret lr
ENDPROC(__after_proc_init)
diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
index 1448f144e7fb9..efebf4120a0c4 100644
--- a/arch/arm/mm/proc-v7m.S
+++ b/arch/arm/mm/proc-v7m.S
@@ -136,9 +136,8 @@ __v7m_setup_cont:
cpsie i
svc #0
1: cpsid i
- ldr r0, =exc_ret
- orr lr, lr, #EXC_RET_THREADMODE_PROCESSSTACK
- str lr, [r0]
+ /* Calculate exc_ret */
+ orr r10, lr, #EXC_RET_THREADMODE_PROCESSSTACK
ldmia sp, {r0-r3, r12}
str r5, [r12, #11 * 4] @ restore the original SVC vector entry
mov lr, r6 @ restore LR
--
2.20.1


\
 
 \ /
  Last update: 2019-11-08 20:06    [W:0.284 / U:0.696 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site