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Using memor clobber for serialization

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Volatile isn't enough to prevent the compiler from reordering the
read/write functions for the control registers and messing everything
up. => We use a memory clobber to serialize the code.
This commit is contained in:
Stefan Lankes 2015-08-28 07:40:44 +02:00
parent 64e0357ea0
commit 5a7cb4e4e0
1 changed files with 20 additions and 8 deletions
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28
hermit/arch/x86/include/asm/processor.h
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@ -379,7 +379,7 @@ inline static void wrmsr(uint32_t msr, uint64_t value)
*/
static inline size_t read_cr0(void) {
size_t val;
asm volatile("mov %%cr0, %0" : "=r"(val));
asm volatile("mov %%cr0, %0" : "=r"(val) :: "memory");
return val;
}
@ -387,7 +387,7 @@ static inline size_t read_cr0(void) {
* @param val The value you want to write into cr0
*/
static inline void write_cr0(size_t val) {
asm volatile("mov %0, %%cr0" : : "r"(val));
asm volatile("mov %0, %%cr0" :: "r"(val) : "memory");
}
/** @brief Read cr2 register
@ -395,7 +395,7 @@ static inline void write_cr0(size_t val) {
*/
static inline size_t read_cr2(void) {
size_t val;
asm volatile("mov %%cr2, %0" : "=r"(val));
asm volatile("mov %%cr2, %0" : "=r"(val) :: "memory");
return val;
}
@ -403,7 +403,7 @@ static inline size_t read_cr2(void) {
* @param val The value you want to write into cr2
*/
static inline void write_cr2(size_t val) {
asm volatile("mov %0, %%cr2" : : "r"(val));
asm volatile("mov %0, %%cr2" :: "r"(val) : "memory");
}
/** @brief Read cr3 register
@ -411,7 +411,7 @@ static inline void write_cr2(size_t val) {
*/
static inline size_t read_cr3(void) {
size_t val;
asm volatile("mov %%cr3, %0" : "=r"(val));
asm volatile("mov %%cr3, %0" : "=r"(val) :: "memory");
return val;
}
@ -419,7 +419,7 @@ static inline size_t read_cr3(void) {
* @param val The value you want to write into cr3
*/
static inline void write_cr3(size_t val) {
asm volatile("mov %0, %%cr3" : : "r"(val));
asm volatile("mov %0, %%cr3" :: "r"(val) : "memory");
}
/** @brief Read cr4 register
@ -427,7 +427,7 @@ static inline void write_cr3(size_t val) {
*/
static inline size_t read_cr4(void) {
size_t val;
asm volatile("mov %%cr4, %0" : "=r"(val));
asm volatile("mov %%cr4, %0" : "=r"(val) :: "memory");
return val;
}
@ -435,7 +435,19 @@ static inline size_t read_cr4(void) {
* @param val The value you want to write into cr4
*/
static inline void write_cr4(size_t val) {
asm volatile("mov %0, %%cr4" : : "r"(val));
asm volatile("mov %0, %%cr4" :: "r"(val) : "memory");
}
static inline size_t read_cr8(void)
{
size_t val;
asm volatile("mov %%cr8, %0" : "=r" (val) :: "memory");
return val;
}
static inline void write_cr8(size_t val)
{
asm volatile("movq %0, %%cr8" :: "r" (val) : "memory");
}
typedef size_t (*func_read_fsgs)(void);