[PATCH] i386: Fix places where using %gs changes the usermode ABI
There are a few places where the change in struct pt_regs and the use of %gs
affect the userspace ABI. These are primarily debugging interfaces where
thread state can be inspected or extracted.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 905364d..dc42725 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -315,8 +315,8 @@
regs->eax,regs->ebx,regs->ecx,regs->edx);
printk("ESI: %08lx EDI: %08lx EBP: %08lx",
regs->esi, regs->edi, regs->ebp);
- printk(" DS: %04x ES: %04x\n",
- 0xffff & regs->xds,0xffff & regs->xes);
+ printk(" DS: %04x ES: %04x GS: %04x\n",
+ 0xffff & regs->xds,0xffff & regs->xes, 0xffff & regs->xgs);
cr0 = read_cr0();
cr2 = read_cr2();
@@ -509,7 +509,7 @@
dump->regs.ds = regs->xds;
dump->regs.es = regs->xes;
savesegment(fs,dump->regs.fs);
- savesegment(gs,dump->regs.gs);
+ dump->regs.gs = regs->xgs;
dump->regs.orig_eax = regs->orig_eax;
dump->regs.eip = regs->eip;
dump->regs.cs = regs->xcs;
diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c
index 775f50e..f3f94ac 100644
--- a/arch/i386/kernel/ptrace.c
+++ b/arch/i386/kernel/ptrace.c
@@ -94,13 +94,9 @@
return -EIO;
child->thread.fs = value;
return 0;
- case GS:
- if (value && (value & 3) != 3)
- return -EIO;
- child->thread.gs = value;
- return 0;
case DS:
case ES:
+ case GS:
if (value && (value & 3) != 3)
return -EIO;
value &= 0xffff;
@@ -116,8 +112,8 @@
value |= get_stack_long(child, EFL_OFFSET) & ~FLAG_MASK;
break;
}
- if (regno > GS*4)
- regno -= 2*4;
+ if (regno > ES*4)
+ regno -= 1*4;
put_stack_long(child, regno - sizeof(struct pt_regs), value);
return 0;
}
@@ -131,18 +127,16 @@
case FS:
retval = child->thread.fs;
break;
- case GS:
- retval = child->thread.gs;
- break;
case DS:
case ES:
+ case GS:
case SS:
case CS:
retval = 0xffff;
/* fall through */
default:
- if (regno > GS*4)
- regno -= 2*4;
+ if (regno > ES*4)
+ regno -= 1*4;
regno = regno - sizeof(struct pt_regs);
retval &= get_stack_long(child, regno);
}
diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h
index 3a05436..45d21a0 100644
--- a/include/asm-i386/elf.h
+++ b/include/asm-i386/elf.h
@@ -91,7 +91,7 @@
pr_reg[7] = regs->xds; \
pr_reg[8] = regs->xes; \
savesegment(fs,pr_reg[9]); \
- savesegment(gs,pr_reg[10]); \
+ pr_reg[10] = regs->xgs; \
pr_reg[11] = regs->orig_eax; \
pr_reg[12] = regs->eip; \
pr_reg[13] = regs->xcs; \
diff --git a/include/asm-i386/unwind.h b/include/asm-i386/unwind.h
index 5031d69..601fc67 100644
--- a/include/asm-i386/unwind.h
+++ b/include/asm-i386/unwind.h
@@ -71,6 +71,7 @@
info->regs.xss = __KERNEL_DS;
info->regs.xds = __USER_DS;
info->regs.xes = __USER_DS;
+ info->regs.xgs = __KERNEL_PDA;
}
extern asmlinkage int arch_unwind_init_running(struct unwind_frame_info *,