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[PATCH] uml: stack usage reduction

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The KSTK_* macros used an inordinate amount of stack.  In order to overcome
an impedance mismatch between their interface, which just returns a single
register value, and the interface of get_thread_regs, which took a full
pt_regs, the implementation created an on-stack pt_regs, filled it in, and
returned one field.  do_task_stat calls KSTK_* twice, resulting in two
local pt_regs, blowing out the stack.

This patch changes the interface (and name) of get_thread_regs to just
return a single register from a jmp_buf.

The include of archsetjmp.h" in registers.h to get the definition of
jmp_buf exposed a bogus include of <setjmp.h> in start_up.c.  <setjmp.h>
shouldn't be used anywhere any more since UML uses the klibc
setjmp/longjmp.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jeff Dike
2006-09-25 23:33:08 -07:00
committed by Linus Torvalds
parent bf61f50d63
commit 75e29b18d9
5 changed files with 21 additions and 17 deletions
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4
include/asm-um/processor-generic.h
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@@ -138,9 +138,7 @@ extern struct cpuinfo_um cpu_data[];
#ifdef CONFIG_MODE_SKAS
#define KSTK_REG(tsk, reg) \
({ union uml_pt_regs regs; \
get_thread_regs(&regs, tsk->thread.mode.skas.switch_buf); \
UPT_REG(&regs, reg); })
get_thread_reg(reg, tsk->thread.mode.skas.switch_buf)
#else
#define KSTK_REG(tsk, reg) (0xbadbabe)
#endif