linux-kernel - [PATCH x86/mm 6/6] x86-64 ia32 ptrace get/putreg32 current task

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Message-Id: <20071129004222.E49AD26F8E7@magilla.localdomain>
Date:	Wed, 28 Nov 2007 16:42:22 -0800 (PST)
From:	Roland McGrath <roland@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH x86/mm 6/6] x86-64 ia32 ptrace get/putreg32 current task


This generalizes the getreg32 and putreg32 functions so they can be used on
the current task, as well as on a task stopped in TASK_TRACED and switched
off.  This lays the groundwork to share this code for all kinds of
user-mode machine state access, not just ptrace.

Signed-off-by: Roland McGrath <roland@...hat.com>
---
 arch/x86/ia32/ptrace32.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/arch/x86/ia32/ptrace32.c b/arch/x86/ia32/ptrace32.c
index c52d066..d5663e2 100644
--- a/arch/x86/ia32/ptrace32.c
+++ b/arch/x86/ia32/ptrace32.c
@@ -48,19 +48,27 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 val)
 		if (val && (val & 3) != 3)
 			return -EIO;
 		child->thread.fsindex = val & 0xffff;
+		if (child == current)
+			loadsegment(fs, child->thread.fsindex);
 		break;
 	case offsetof(struct user32, regs.gs):
 		if (val && (val & 3) != 3)
 			return -EIO;
 		child->thread.gsindex = val & 0xffff;
+		if (child == current)
+			load_gs_index(child->thread.gsindex);
 		break;
 	case offsetof(struct user32, regs.ds):
 		if (val && (val & 3) != 3)
 			return -EIO;
 		child->thread.ds = val & 0xffff;
+		if (child == current)
+			loadsegment(ds, child->thread.ds);
 		break;
 	case offsetof(struct user32, regs.es):
 		child->thread.es = val & 0xffff;
+		if (child == current)
+			loadsegment(es, child->thread.ds);
 		break;
 	case offsetof(struct user32, regs.ss):
 		if ((val & 3) != 3)
@@ -129,15 +137,23 @@ static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
 	switch (regno) {
 	case offsetof(struct user32, regs.fs):
 		*val = child->thread.fsindex;
+		if (child == current)
+			asm("movl %%fs,%0" : "=r" (*val));
 		break;
 	case offsetof(struct user32, regs.gs):
 		*val = child->thread.gsindex;
+		if (child == current)
+			asm("movl %%gs,%0" : "=r" (*val));
 		break;
 	case offsetof(struct user32, regs.ds):
 		*val = child->thread.ds;
+		if (child == current)
+			asm("movl %%ds,%0" : "=r" (*val));
 		break;
 	case offsetof(struct user32, regs.es):
 		*val = child->thread.es;
+		if (child == current)
+			asm("movl %%es,%0" : "=r" (*val));
 		break;
 
 	R32(cs, cs);
-
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