The patch titled
uml: stack usage reduction
has been added to the -mm tree. Its filename is
uml-stack-usage-reduction.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: uml: stack usage reduction
From: Jeff Dike <jdike@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/um/include/registers.h | 3 ++-
arch/um/os-Linux/start_up.c | 1 -
arch/um/os-Linux/sys-i386/registers.c | 15 +++++++++------
arch/um/os-Linux/sys-x86_64/registers.c | 15 +++++++++------
include/asm-um/processor-generic.h | 4 +---
5 files changed, 21 insertions(+), 17 deletions(-)
diff -puN arch/um/include/registers.h~uml-stack-usage-reduction arch/um/include/registers.h
--- a/arch/um/include/registers.h~uml-stack-usage-reduction
+++ a/arch/um/include/registers.h
@@ -7,6 +7,7 @@
#define __REGISTERS_H
#include "sysdep/ptrace.h"
+#include "sysdep/archsetjmp.h"
extern void init_thread_registers(union uml_pt_regs *to);
extern int save_fp_registers(int pid, unsigned long *fp_regs);
@@ -15,6 +16,6 @@ extern void save_registers(int pid, unio
extern void restore_registers(int pid, union uml_pt_regs *regs);
extern void init_registers(int pid);
extern void get_safe_registers(unsigned long * regs, unsigned long * fp_regs);
-extern void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer);
+extern unsigned long get_thread_reg(int reg, jmp_buf *buf);
#endif
diff -puN arch/um/os-Linux/start_up.c~uml-stack-usage-reduction arch/um/os-Linux/start_up.c
--- a/arch/um/os-Linux/start_up.c~uml-stack-usage-reduction
+++ a/arch/um/os-Linux/start_up.c
@@ -14,7 +14,6 @@
#include <sched.h>
#include <fcntl.h>
#include <errno.h>
-#include <setjmp.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/mman.h>
diff -puN arch/um/os-Linux/sys-i386/registers.c~uml-stack-usage-reduction arch/um/os-Linux/sys-i386/registers.c
--- a/arch/um/os-Linux/sys-i386/registers.c~uml-stack-usage-reduction
+++ a/arch/um/os-Linux/sys-i386/registers.c
@@ -130,11 +130,14 @@ void get_safe_registers(unsigned long *r
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, EIP, jmpbuf->__eip);
- UPT_SET(uml_regs, UESP, jmpbuf->__esp);
- UPT_SET(uml_regs, EBP, jmpbuf->__ebp);
+ switch(reg){
+ case EIP: return buf[0]->__eip;
+ case UESP: return buf[0]->__esp;
+ case EBP: return buf[0]->__ebp;
+ default:
+ printk("get_thread_regs - unknown register %d\n", reg);
+ return 0;
+ }
}
diff -puN arch/um/os-Linux/sys-x86_64/registers.c~uml-stack-usage-reduction arch/um/os-Linux/sys-x86_64/registers.c
--- a/arch/um/os-Linux/sys-x86_64/registers.c~uml-stack-usage-reduction
+++ a/arch/um/os-Linux/sys-x86_64/registers.c
@@ -78,11 +78,14 @@ void get_safe_registers(unsigned long *r
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;
+ }
}
diff -puN include/asm-um/processor-generic.h~uml-stack-usage-reduction include/asm-um/processor-generic.h
--- a/include/asm-um/processor-generic.h~uml-stack-usage-reduction
+++ a/include/asm-um/processor-generic.h
@@ -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(®s, tsk->thread.mode.skas.switch_buf); \
- UPT_REG(®s, reg); })
+ get_thread_reg(reg, tsk->thread.mode.skas.switch_buf)
#else
#define KSTK_REG(tsk, reg) (0xbadbabe)
#endif
_
Patches currently in -mm which might be from jdike@xxxxxxxxxxx are
fix-x86_64-mm-i386-semaphore-to-asm-uml-fix.patch
reduce-max_nr_zones-make-zone_highmem-optional-fix-fix-fix.patch
split-i386-and-x86_64-ptraceh.patch
uml-use-ptrace-abih-instead-of-ptraceh.patch
uml-use-klibc-setjmp-longjmp.patch
uml-use-array_size-more-assiduously.patch
uml-fix-stack-alignment.patch
uml-whitespace-fixes.patch
uml-fix-handling-of-failed-execs-of-helpers.patch
uml-improve-sigbus-diagnostics.patch
uml-sigio-cleanups.patch
uml-move-signal-handlers-to-arch-code.patch
uml-move-signal-handlers-to-arch-code-fix.patch
uml-timer-cleanups.patch
uml-remove-unused-variable.patch
uml-clean-our-set_ether_mac.patch
uml-stack-usage-reduction.patch
uml-use-mcmodel=kernel-for-x86_64.patch
uml-fix-proc-vs-interrupt-context-spinlock-deadlock.patch
uml-remove-pte_mkexec.patch
namespaces-utsname-switch-to-using-uts-namespaces-uml-fix.patch
-
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