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Subject[PATCH v2 5/6] x86: Remove INIT_TSS and fold the definitions into cpu_tss
Date
The INIT_TSS is unnecessary.  Just define the initial TSS where cpu_tss
is defined.

While we're at it, merge the 32-bit and 64-bit definitions. The only
syntactic change is that 32-bit kernels were computing sp0 as long, but
now they compute it as unsigned long.

Verified by objdump: the contents and relocations of
.data..percpu..shared_aligned are unchanged on 32-bit and 64-bit
kernels.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
arch/x86/include/asm/processor.h | 20 --------------------
arch/x86/kernel/process.c | 20 +++++++++++++++++++-
2 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 117ee65473e2..f5e3ec63767d 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -818,22 +818,6 @@ static inline void spin_lock_prefetch(const void *x)
.io_bitmap_ptr = NULL, \
}

-/*
- * Note that the .io_bitmap member must be extra-big. This is because
- * the CPU will access an additional byte beyond the end of the IO
- * permission bitmap. The extra byte must be all 1 bits, and must
- * be within the limit.
- */
-#define INIT_TSS { \
- .x86_tss = { \
- .sp0 = sizeof(init_stack) + (long)&init_stack, \
- .ss0 = __KERNEL_DS, \
- .ss1 = __KERNEL_CS, \
- .io_bitmap_base = INVALID_IO_BITMAP_OFFSET, \
- }, \
- .io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 }, \
-}
-
extern unsigned long thread_saved_pc(struct task_struct *tsk);

#define THREAD_SIZE_LONGS (THREAD_SIZE/sizeof(unsigned long))
@@ -892,10 +876,6 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk);
.sp0 = (unsigned long)&init_stack + sizeof(init_stack) \
}

-#define INIT_TSS { \
- .x86_tss.sp0 = (unsigned long)&init_stack + sizeof(init_stack) \
-}
-
/*
* Return saved PC of a blocked thread.
* What is this good for? it will be always the scheduler or ret_from_fork.
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 6f6087349231..f4c0af7fc3a0 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -37,7 +37,25 @@
* section. Since TSS's are completely CPU-local, we want them
* on exact cacheline boundaries, to eliminate cacheline ping-pong.
*/
-__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = INIT_TSS;
+__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
+ .x86_tss = {
+ .sp0 = (unsigned long)&init_stack + sizeof(init_stack),
+#ifdef CONFIG_X86_32
+ .ss0 = __KERNEL_DS,
+ .ss1 = __KERNEL_CS,
+ .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
+#endif
+ },
+#ifdef CONFIG_X86_32
+ /*
+ * Note that the .io_bitmap member must be extra-big. This is because
+ * the CPU will access an additional byte beyond the end of the IO
+ * permission bitmap. The extra byte must be all 1 bits, and must
+ * be within the limit.
+ */
+ .io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 },
+#endif
+};
EXPORT_PER_CPU_SYMBOL_GPL(cpu_tss);

#ifdef CONFIG_X86_64
--
2.1.0


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