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Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

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Pull ARM fixes from Russell King:
 "Another round of small ARM fixes.

  restore_user_regs early stack deallocation is buggy in the presence of
  FIQs which switch to SVC mode, and could lead to corrupted registers
  being returned to a user process given an inopportune FIQ event.

  Another bug was spotted in the ARM perf code where it could lose track
  of perf counter overflows, leading to incorrect perf results.

  Lastly, a bug in arm_add_memory() was spotted where the memory sizes
  aren't properly rounded.  As most people pass properly rounded sizes,
  this hasn't been noticed"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8292/1: mm: fix size rounding-down of arm_add_memory() function
  ARM: 8255/1: perf: Prevent wraparound during overflow
  ARM: 8266/1: Remove early stack deallocation from restore_user_regs
This commit is contained in:
Linus Torvalds 2015-01-24 09:57:01 +12:00
commit 0ad4989d62
3 changed files with 20 additions and 10 deletions
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13
arch/arm/kernel/entry-header.S
View File

@ -253,21 +253,22 @@
.endm
.macro restore_user_regs, fast = 0, offset = 0
ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr
ldr lr, [sp, #\offset + S_PC]! @ get pc
mov r2, sp
ldr r1, [r2, #\offset + S_PSR] @ get calling cpsr
ldr lr, [r2, #\offset + S_PC]! @ get pc
msr spsr_cxsf, r1 @ save in spsr_svc
#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K)
@ We must avoid clrex due to Cortex-A15 erratum #830321
strex r1, r2, [sp] @ clear the exclusive monitor
strex r1, r2, [r2] @ clear the exclusive monitor
#endif
.if \fast
ldmdb sp, {r1 - lr}^ @ get calling r1 - lr
ldmdb r2, {r1 - lr}^ @ get calling r1 - lr
.else
ldmdb sp, {r0 - lr}^ @ get calling r0 - lr
ldmdb r2, {r0 - lr}^ @ get calling r0 - lr
.endif
mov r0, r0 @ ARMv5T and earlier require a nop
@ after ldm {}^
add sp, sp, #S_FRAME_SIZE - S_PC
add sp, sp, #\offset + S_FRAME_SIZE
movs pc, lr @ return & move spsr_svc into cpsr
.endm

10
arch/arm/kernel/perf_event.c
View File

@ -116,8 +116,14 @@ int armpmu_event_set_period(struct perf_event *event)
ret = 1;
}
if (left > (s64)armpmu->max_period)
left = armpmu->max_period;
/*
* Limit the maximum period to prevent the counter value
* from overtaking the one we are about to program. In
* effect we are reducing max_period to account for
* interrupt latency (and we are being very conservative).
*/
if (left > (armpmu->max_period >> 1))
left = armpmu->max_period >> 1;
local64_set(&hwc->prev_count, (u64)-left);

7
arch/arm/kernel/setup.c
View File

@ -657,10 +657,13 @@ int __init arm_add_memory(u64 start, u64 size)
/*
* Ensure that start/size are aligned to a page boundary.
* Size is appropriately rounded down, start is rounded up.
* Size is rounded down, start is rounded up.
*/
size -= start & ~PAGE_MASK;
aligned_start = PAGE_ALIGN(start);
if (aligned_start > start + size)
size = 0;
else
size -= aligned_start - start;
#ifndef CONFIG_ARCH_PHYS_ADDR_T_64BIT
if (aligned_start > ULONG_MAX) {