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ARM: smp_on_up: move inline asm ALT_SMP patching macro out of spinlock.h

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Patching UP/SMP alternatives inside inline assembly blocks is useful
outside of the spinlock implementation, where it is used for sev and wfe.

This patch lifts the macro into processor.h and gives it a scarier name
to (a) avoid conflicts in the global namespace and (b) to try and deter
its usage unless you "know what you're doing". The W macro for generating
wide instructions when targetting Thumb-2 is also made available under
the name WASM, to reduce the potential for conflicts with other headers.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2013-07-02 12:10:42 +01:00
parent e744dff72b
commit 27a84793e4
3 changed files with 20 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/arm/include/asm/processor.h
View File

@ -22,6 +22,7 @@
#include <asm/hw_breakpoint.h>
#include <asm/ptrace.h>
#include <asm/types.h>
#include <asm/unified.h>
#ifdef __KERNEL__
#define STACK_TOP ((current->personality & ADDR_LIMIT_32BIT) ? \
@ -87,6 +88,17 @@ unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) task_pt_regs(tsk)->ARM_pc
#define KSTK_ESP(tsk) task_pt_regs(tsk)->ARM_sp
#ifdef CONFIG_SMP
#define __ALT_SMP_ASM(smp, up) \
"9998: " smp "\n" \
" .pushsection \".alt.smp.init\", \"a\"\n" \
" .long 9998b\n" \
" " up "\n" \
" .popsection\n"
#else
#define __ALT_SMP_ASM(smp, up) up
#endif
/*
* Prefetching support - only ARMv5.
*/

15
arch/arm/include/asm/spinlock.h
View File

@ -11,15 +11,7 @@
* sev and wfe are ARMv6K extensions. Uniprocessor ARMv6 may not have the K
* extensions, so when running on UP, we have to patch these instructions away.
*/
#define ALT_SMP(smp, up) \
"9998: " smp "\n" \
" .pushsection \".alt.smp.init\", \"a\"\n" \
" .long 9998b\n" \
" " up "\n" \
" .popsection\n"
#ifdef CONFIG_THUMB2_KERNEL
#define SEV ALT_SMP("sev.w", "nop.w")
/*
* For Thumb-2, special care is needed to ensure that the conditional WFE
* instruction really does assemble to exactly 4 bytes (as required by
@ -31,17 +23,18 @@
* the assembler won't change IT instructions which are explicitly present
* in the input.
*/
#define WFE(cond) ALT_SMP( \
#define WFE(cond) __ALT_SMP_ASM( \
"it " cond "\n\t" \
"wfe" cond ".n", \
\
"nop.w" \
)
#else
#define SEV ALT_SMP("sev", "nop")
#define WFE(cond) ALT_SMP("wfe" cond, "nop")
#define WFE(cond) __ALT_SMP_ASM("wfe" cond, "nop")
#endif
#define SEV __ALT_SMP_ASM(WASM(sev), WASM(nop))
static inline void dsb_sev(void)
{
#if __LINUX_ARM_ARCH__ >= 7

4
arch/arm/include/asm/unified.h
View File

@ -38,6 +38,8 @@
#ifdef __ASSEMBLY__
#define W(instr) instr.w
#define BSYM(sym) sym + 1
#else
#define WASM(instr) #instr ".w"
#endif
#else /* !CONFIG_THUMB2_KERNEL */
@ -50,6 +52,8 @@
#ifdef __ASSEMBLY__
#define W(instr) instr
#define BSYM(sym) sym
#else
#define WASM(instr) #instr
#endif
#endif /* CONFIG_THUMB2_KERNEL */