diff options
author | Jeff Dike <jdike@addtoit.com> | 2006-09-25 23:33:08 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-26 08:49:09 -0700 |
commit | 75e29b18d9a46bf3193278e92dc95609a8cca2ab (patch) | |
tree | 413935160ac2f65c13ec5260a60cdd1d9259fd83 /arch/um/os-Linux/sys-x86_64/registers.c | |
parent | bf61f50d63b4d9e30d7a86a2d44bb300ae7c1dd4 (diff) |
[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>
Diffstat (limited to 'arch/um/os-Linux/sys-x86_64/registers.c')
-rw-r--r-- | arch/um/os-Linux/sys-x86_64/registers.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/arch/um/os-Linux/sys-x86_64/registers.c b/arch/um/os-Linux/sys-x86_64/registers.c index e730447d6c02..cb8e8a263280 100644 --- a/arch/um/os-Linux/sys-x86_64/registers.c +++ b/arch/um/os-Linux/sys-x86_64/registers.c @@ -78,11 +78,14 @@ void get_safe_registers(unsigned long *regs, unsigned long *fp_regs) HOST_FP_SIZE * sizeof(unsigned long)); } -void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer) +unsigned long get_thread_reg(int reg, jmp_buf *buf) { - struct __jmp_buf *jmpbuf = buffer; - - UPT_SET(uml_regs, RIP, jmpbuf->__rip); - UPT_SET(uml_regs, RSP, jmpbuf->__rsp); - UPT_SET(uml_regs, RBP, jmpbuf->__rbp); + switch(reg){ + case RIP: return buf[0]->__rip; + case RSP: return buf[0]->__rsp; + case RBP: return buf[0]->__rbp; + default: + printk("get_thread_regs - unknown register %d\n", reg); + return 0; + } } |