mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-15 11:36:41 +07:00
568dca15aa
Patrik Kluba reports that the preempt count becomes invalid due to the preempt_enable() call being unbalanced with a preempt_disable() call in the vfp assembly routines. This happens because preempt_enable() and preempt_disable() update preempt counts under PREEMPT_COUNT=y but the vfp assembly routines do so under PREEMPT=y. In a configuration where PREEMPT=n and DEBUG_ATOMIC_SLEEP=y, PREEMPT_COUNT=y and so the preempt_enable() call in VFP_bounce() keeps subtracting from the preempt count until it goes negative. Fix this by always using PREEMPT_COUNT to decided when to update preempt counts in the ARM assembly code. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Reported-by: Patrik Kluba <pkluba@dension.com> Tested-by: Patrik Kluba <pkluba@dension.com> Cc: <stable@vger.kernel.org> # 2.6.30 Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
72 lines
1.8 KiB
ArmAsm
72 lines
1.8 KiB
ArmAsm
/*
|
|
* linux/arch/arm/vfp/entry.S
|
|
*
|
|
* Copyright (C) 2004 ARM Limited.
|
|
* Written by Deep Blue Solutions Limited.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#include <asm/thread_info.h>
|
|
#include <asm/vfpmacros.h>
|
|
#include "../kernel/entry-header.S"
|
|
|
|
@ VFP entry point.
|
|
@
|
|
@ r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
|
|
@ r2 = PC value to resume execution after successful emulation
|
|
@ r9 = normal "successful" return address
|
|
@ r10 = this threads thread_info structure
|
|
@ lr = unrecognised instruction return address
|
|
@ IRQs disabled.
|
|
@
|
|
ENTRY(do_vfp)
|
|
#ifdef CONFIG_PREEMPT_COUNT
|
|
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
|
|
add r11, r4, #1 @ increment it
|
|
str r11, [r10, #TI_PREEMPT]
|
|
#endif
|
|
enable_irq
|
|
ldr r4, .LCvfp
|
|
ldr r11, [r10, #TI_CPU] @ CPU number
|
|
add r10, r10, #TI_VFPSTATE @ r10 = workspace
|
|
ldr pc, [r4] @ call VFP entry point
|
|
ENDPROC(do_vfp)
|
|
|
|
ENTRY(vfp_null_entry)
|
|
#ifdef CONFIG_PREEMPT_COUNT
|
|
get_thread_info r10
|
|
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
|
|
sub r11, r4, #1 @ decrement it
|
|
str r11, [r10, #TI_PREEMPT]
|
|
#endif
|
|
mov pc, lr
|
|
ENDPROC(vfp_null_entry)
|
|
|
|
.align 2
|
|
.LCvfp:
|
|
.word vfp_vector
|
|
|
|
@ This code is called if the VFP does not exist. It needs to flag the
|
|
@ failure to the VFP initialisation code.
|
|
|
|
__INIT
|
|
ENTRY(vfp_testing_entry)
|
|
#ifdef CONFIG_PREEMPT_COUNT
|
|
get_thread_info r10
|
|
ldr r4, [r10, #TI_PREEMPT] @ get preempt count
|
|
sub r11, r4, #1 @ decrement it
|
|
str r11, [r10, #TI_PREEMPT]
|
|
#endif
|
|
ldr r0, VFP_arch_address
|
|
str r5, [r0] @ known non-zero value
|
|
mov pc, r9 @ we have handled the fault
|
|
ENDPROC(vfp_testing_entry)
|
|
|
|
.align 2
|
|
VFP_arch_address:
|
|
.word VFP_arch
|
|
|
|
__FINIT
|