commit 75e29b18d9a46bf3193278e92dc95609a8cca2ab
author Jeff Dike <jdike@addtoit.com> Mon Sep 25 23:33:08 2006 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> Tue Sep 26 08:49:09 2006 -0700
tree 413935160ac2f65c13ec5260a60cdd1d9259fd83
parent bf61f50d63b4d9e30d7a86a2d44bb300ae7c1dd4

[PATCH] uml: stack usage reduction

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>

include/asm-um/processor-generic.h

diff --git a/include/asm-um/processor-generic.h b/include/asm-um/processor-generic.h
index 824c288..afa4fe1 100644
--- a/include/asm-um/processor-generic.h
+++ b/include/asm-um/processor-generic.h
@@ -138,9 +138,7 @@
 
 #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