[Devel] [PATCH 4/9] x86_32: add TIF_IA32 to thread flags

[serue at us.ibm.com]

From: Serge E. Hallyn <serue at us.ibm.com>

X86-32 does not set TIF_IA32 on tasks.  But since we now use the
same CKPT_ARCH_ID for X86-32 and X86-64, this means that when we
restart a task from X86-32 on X86-64, we can't tell that it should
have been 32-bit.

So always set TIF_IA32 in thread_info_flags for a task when
checkpointing on X86-32.

Likewise, at restart, when comparing the current task (the running
restart binary) to the checkpointed one (to be restarted) to make
sure both are either 32-bit or 64-bit, we obviously can't count
on TIF_IA32 being set in current_flags on X86-32.

Signed-off-by: Serge E. Hallyn <serue at us.ibm.com>
---
 arch/x86/kernel/checkpoint.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/checkpoint.c b/arch/x86/kernel/checkpoint.c
index b01a2fc..961b131 100644
--- a/arch/x86/kernel/checkpoint.c
+++ b/arch/x86/kernel/checkpoint.c
@@ -103,6 +103,9 @@ int checkpoint_thread(struct ckpt_ctx *ctx, struct task_struct *t)
 
 	h->thread_info_flags =
 		task_thread_info(t)->flags & ~CKPT_X86_TIF_UNSUPPORTED;
+#ifndef CONFIG_X86_64
+	h->thread_info_flags |= _TIF_IA32;
+#endif
 	h->gdt_entry_tls_entries = GDT_ENTRY_TLS_ENTRIES;
 	h->sizeof_tls_array = tls_size;
 
@@ -289,7 +292,11 @@ int restore_thread(struct ckpt_ctx *ctx)
 		 * Eventually we'd like to support mixed-bit restart, but for
 		 * now don't pretend to.
 		 */
+#ifndef CONFIG_X86_64
+		pre = 1;
+#else
 		pre = test_thread_flag(TIF_IA32);
+#endif
 		post = h->thread_info_flags & _TIF_IA32;
 		if ((pre && !post) || (post && !pre)) {
 			ret = -EINVAL;
-- 
1.6.0.4

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