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Date: Tue, 13 Jan 2009 19:38:15 +0900
From: Tejun Heo <tj@...nel.org>
To: ebiederm@...ssion.com, cl@...ux-foundation.org,
rusty@...tcorp.com.au, mingo@...e.hu, travis@....com,
linux-kernel@...r.kernel.org, hpa@...or.com,
akpm@...ux-foundation.org, steiner@....com, hugh@...itas.com
Cc: Tejun Heo <tj@...nel.org>
Subject: [PATCH 11/13] x86_64: convert pda ops to wrappers around x86 percpu accessors
pda is now a percpu variable and there's no reason it can't use plain
x86 percpu accessors. Add x86_test_and_clear_bit_percpu() and replace
pda op implementations with wrappers around x86 percpu accessors.
Signed-off-by: Tejun Heo <tj@...nel.org>
---
arch/x86/include/asm/pda.h | 88 +++-----------------------------------
arch/x86/include/asm/percpu.h | 10 ++++
arch/x86/kernel/vmlinux_64.lds.S | 1 -
arch/x86/kernel/x8664_ksyms_64.c | 2 -
4 files changed, 16 insertions(+), 85 deletions(-)
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
index 66ae104..e3d3a08 100644
--- a/arch/x86/include/asm/pda.h
+++ b/arch/x86/include/asm/pda.h
@@ -45,91 +45,15 @@ extern void pda_init(int);
#define cpu_pda(cpu) (&per_cpu(__pda, cpu))
-/*
- * There is no fast way to get the base address of the PDA, all the accesses
- * have to mention %fs/%gs. So it needs to be done this Torvaldian way.
- */
-extern void __bad_pda_field(void) __attribute__((noreturn));
-
-/*
- * proxy_pda doesn't actually exist, but tell gcc it is accessed for
- * all PDA accesses so it gets read/write dependencies right.
- */
-extern struct x8664_pda _proxy_pda;
-
-#define pda_offset(field) offsetof(struct x8664_pda, field)
-
-#define pda_to_op(op, field, val) \
-do { \
- typedef typeof(_proxy_pda.field) T__; \
- if (0) { T__ tmp__; tmp__ = (val); } /* type checking */ \
- switch (sizeof(_proxy_pda.field)) { \
- case 2: \
- asm(op "w %1,%%gs:%c2" : \
- "+m" (_proxy_pda.field) : \
- "ri" ((T__)val), \
- "i"(pda_offset(field))); \
- break; \
- case 4: \
- asm(op "l %1,%%gs:%c2" : \
- "+m" (_proxy_pda.field) : \
- "ri" ((T__)val), \
- "i" (pda_offset(field))); \
- break; \
- case 8: \
- asm(op "q %1,%%gs:%c2": \
- "+m" (_proxy_pda.field) : \
- "r" ((T__)val), \
- "i"(pda_offset(field))); \
- break; \
- default: \
- __bad_pda_field(); \
- } \
-} while (0)
-
-#define pda_from_op(op, field) \
-({ \
- typeof(_proxy_pda.field) ret__; \
- switch (sizeof(_proxy_pda.field)) { \
- case 2: \
- asm(op "w %%gs:%c1,%0" : \
- "=r" (ret__) : \
- "i" (pda_offset(field)), \
- "m" (_proxy_pda.field)); \
- break; \
- case 4: \
- asm(op "l %%gs:%c1,%0": \
- "=r" (ret__): \
- "i" (pda_offset(field)), \
- "m" (_proxy_pda.field)); \
- break; \
- case 8: \
- asm(op "q %%gs:%c1,%0": \
- "=r" (ret__) : \
- "i" (pda_offset(field)), \
- "m" (_proxy_pda.field)); \
- break; \
- default: \
- __bad_pda_field(); \
- } \
- ret__; \
-})
-
-#define read_pda(field) pda_from_op("mov", field)
-#define write_pda(field, val) pda_to_op("mov", field, val)
-#define add_pda(field, val) pda_to_op("add", field, val)
-#define sub_pda(field, val) pda_to_op("sub", field, val)
-#define or_pda(field, val) pda_to_op("or", field, val)
+#define read_pda(field) x86_read_percpu(__pda.field)
+#define write_pda(field, val) x86_write_percpu(__pda.field, val)
+#define add_pda(field, val) x86_add_percpu(__pda.field, val)
+#define sub_pda(field, val) x86_sub_percpu(__pda.field, val)
+#define or_pda(field, val) x86_or_percpu(__pda.field, val)
/* This is not atomic against other CPUs -- CPU preemption needs to be off */
#define test_and_clear_bit_pda(bit, field) \
-({ \
- int old__; \
- asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0" \
- : "=r" (old__), "+m" (_proxy_pda.field) \
- : "dIr" (bit), "i" (pda_offset(field)) : "memory");\
- old__; \
-})
+ x86_test_and_clear_bit_percpu(bit, __pda.field)
#endif
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 556f84b..328b31a 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -121,6 +121,16 @@ do { \
#define x86_sub_percpu(var, val) percpu_to_op("sub", per_cpu__##var, val)
#define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val)
+/* This is not atomic against other CPUs -- CPU preemption needs to be off */
+#define x86_test_and_clear_bit_percpu(bit, var) \
+({ \
+ int old__; \
+ asm volatile("btr %1,"__percpu_seg_str"%c2\n\tsbbl %0,%0" \
+ : "=r" (old__) \
+ : "dIr" (bit), "i" (&per_cpu__##var) : "memory"); \
+ old__; \
+})
+
#ifdef CONFIG_X86_64
extern void load_pda_offset(int cpu);
#else
diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index d2a0baa..a09abb8 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -14,7 +14,6 @@ OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
OUTPUT_ARCH(i386:x86-64)
ENTRY(phys_startup_64)
jiffies_64 = jiffies;
-_proxy_pda = 1;
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
data PT_LOAD FLAGS(7); /* RWE */
diff --git a/arch/x86/kernel/x8664_ksyms_64.c b/arch/x86/kernel/x8664_ksyms_64.c
index 695e426..3909e3b 100644
--- a/arch/x86/kernel/x8664_ksyms_64.c
+++ b/arch/x86/kernel/x8664_ksyms_64.c
@@ -58,5 +58,3 @@ EXPORT_SYMBOL(__memcpy);
EXPORT_SYMBOL(empty_zero_page);
EXPORT_SYMBOL(init_level4_pgt);
EXPORT_SYMBOL(load_gs_index);
-
-EXPORT_SYMBOL(_proxy_pda);
--
1.5.6
--
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