Skip to contentSkip to conversation

restart only same bit-ness

PATCH In review Serge E. Hallyn 2 participants 2 messages Feb 8, 2010 1 message not in the archive x86

lore
Share & tools
lore

Serge E. Hallyn

author
#0 lore raw

PATCH 1/1 restart only same bit-ness

v19-rc3 actually tries to reset the TIF_IA32 flag according to how it was set at checkpoint. It should not, at least for now.

Signed-off-by Serge E. Hallyn <serue-r/[email protected]>
---
 arch/x86/kernel/checkpoint.c |   21 +++++++++++++++------
 1 files changed, 15 insertions(+), 6 deletions(-)
arch/x86/kernel/checkpoint.c +15 -6
index 5952e27..b01a2fc 100644
@@ -283,12 +283,21 @@ int restore_thread(struct ckpt_ctx *ctx)
 	load_TLS(thread, cpu);
 	put_cpu();
 
-#if defined(CONFIG_X86_64) && defined(CONFIG_COMPAT)
-	if (h->thread_info_flags & _TIF_IA32)
-		set_thread_flag(TIF_IA32);
-	else
-		clear_thread_flag(TIF_IA32);
-#endif
+	{
+		int pre, post;
+		/*
+		 * Eventually we'd like to support mixed-bit restart, but for
+		 * now don't pretend to.
+		 */
+		pre = test_thread_flag(TIF_IA32);
+		post = h->thread_info_flags & _TIF_IA32;
+		if ((pre && !post) || (post && !pre)) {
+			ret = -EINVAL;
+			ckpt_err(ctx, ret, "%d-bit restarting %d-bit\n",
+				pre ? 32 : 64, post ? 32 : 64);
+			goto out;
+		}
+	}
 
 	/* TODO: restore TIF flags as necessary (e.g. TIF_NOTSC) */
Signature · 1 line
1.6.0.4

A message that is not in the archive (sent off-list or not yet received): 20100208170555.GA16943-r/[email protected]

Reviewed-by
#2 lore raw
Quoted 4 lines · Serge E. Hallyn

v19-rc3 actually tries to reset the TIF_IA32 flag according to how it was set at checkpoint. It should not, at least for now.

Signed-off-by Serge E. Hallyn <serue-r/[email protected]>
Reviewed-by Matt Helsley <matthltc-r/[email protected]>
Quoted 17 lines
---
 arch/x86/kernel/checkpoint.c |   21 +++++++++++++++------
 1 files changed, 15 insertions(+), 6 deletions(-)
arch/x86/kernel/checkpoint.c +0 -5
index 5952e27..b01a2fc 100644
@@ -283,12 +283,21 @@ int restore_thread(struct ckpt_ctx *ctx)
 	load_TLS(thread, cpu);
 	put_cpu();
 
-#if defined(CONFIG_X86_64) && defined(CONFIG_COMPAT)
-	if (h->thread_info_flags & _TIF_IA32)
-		set_thread_flag(TIF_IA32);
-	else
-		clear_thread_flag(TIF_IA32);

arch/x86/kernel/checkpoint.c int restore_thread(struct ckpt_ctx *ctx) · line 294

Quoted 10 lines
arch/x86/kernel/checkpoint.c +9 -1
-#endif
+	{
+		int pre, post;
+		/*
+		 * Eventually we'd like to support mixed-bit restart, but for
+		 * now don't pretend to.
+		 */
+		pre = test_thread_flag(TIF_IA32);
+		post = h->thread_info_flags & _TIF_IA32;
+		if ((pre && !post) || (post && !pre)) {

This might be clearer:

		pre = test_thread_flag(TIF_IA32);
		post = !!(h->thread_info_flags & _TIF_IA32);
		if (pre != post) {

Cheers,
-Matt Helsley