Updates to i386-pda:
- fix typo
- add a self-pointer to the PDA, so that finding its
linear address is easy
- add type checking to PDA write operations
- add byte-sized read/writes to the PDA
Signed-off-by: Jeremy Fitzhardinge <[email protected]>
---
arch/i386/kernel/cpu/common.c | 4 +++-
include/asm-i386/pda.h | 19 +++++++++++++++++++
2 files changed, 22 insertions(+), 1 deletion(-)
diff -r 69614542c834 arch/i386/kernel/cpu/common.c
--- a/arch/i386/kernel/cpu/common.c Fri Sep 08 16:53:26 2006 -0700
+++ b/arch/i386/kernel/cpu/common.c Sat Sep 09 00:19:48 2006 -0700
@@ -588,7 +588,7 @@ void __init early_cpu_init(void)
#endif
}
-/* Make sure %gs it initialized properly in idle threads */
+/* Make sure %gs is initialized properly in idle threads */
struct pt_regs * __devinit idle_regs(struct pt_regs *regs)
{
memset(regs, 0, sizeof(struct pt_regs));
@@ -648,6 +648,8 @@ static __cpuinit void pda_init(int cpu,
memset(pda, 0, sizeof(*pda));
+ pda->_pda = pda;
+
pda->cpu_number = cpu;
pda->pcurrent = curr;
diff -r 69614542c834 include/asm-i386/pda.h
--- a/include/asm-i386/pda.h Fri Sep 08 16:53:26 2006 -0700
+++ b/include/asm-i386/pda.h Sat Sep 09 00:19:48 2006 -0700
@@ -3,6 +3,8 @@
struct i386_pda
{
+ struct i386_pda *_pda; /* pointer to self */
+
struct task_struct *pcurrent; /* current process */
int cpu_number;
};
@@ -20,7 +22,14 @@ extern struct i386_pda _proxy_pda;
#define pda_to_op(op,field,val) \
do { \
typedef typeof(_proxy_pda.field) T__; \
+ if (0) { T__ tmp__; tmp__ = (val); } \
switch (sizeof(_proxy_pda.field)) { \
+ case 1: \
+ asm(op "b %1,%%gs:%c2" \
+ : "+m" (_proxy_pda.field) \
+ :"ri" ((T__)val), \
+ "i"(pda_offset(field))); \
+ break; \
case 2: \
asm(op "w %1,%%gs:%c2" \
: "+m" (_proxy_pda.field) \
@@ -41,6 +50,12 @@ extern struct i386_pda _proxy_pda;
({ \
typeof(_proxy_pda.field) ret__; \
switch (sizeof(_proxy_pda.field)) { \
+ case 1: \
+ asm(op "b %%gs:%c1,%0" \
+ : "=r" (ret__) \
+ : "i" (pda_offset(field)), \
+ "m" (_proxy_pda.field)); \
+ break; \
case 2: \
asm(op "w %%gs:%c1,%0" \
: "=r" (ret__) \
@@ -57,6 +72,10 @@ extern struct i386_pda _proxy_pda;
} \
ret__; })
+/* Return a pointer to a pda field */
+#define pda_addr(field) \
+ ((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \
+ pda_offset(field)))
#define read_pda(field) pda_from_op("mov",field)
#define write_pda(field,val) pda_to_op("mov",field,val)
On Sat, Sep 09, 2006 at 01:15:30AM -0700, Jeremy Fitzhardinge wrote:
>
> -/* Make sure %gs it initialized properly in idle threads */
> +/* Make sure %gs is initialized properly in idle threads */
Merged
> };
> @@ -20,7 +22,14 @@ extern struct i386_pda _proxy_pda;
> #define pda_to_op(op,field,val) \
> do { \
> typedef typeof(_proxy_pda.field) T__; \
> + if (0) { T__ tmp__; tmp__ = (val); } \
Merged into original patch
> switch (sizeof(_proxy_pda.field)) { \
> + case 1: \
> + asm(op "b %1,%%gs:%c2" \
> + : "+m" (_proxy_pda.field) \
> + :"ri" ((T__)val), \
> + "i"(pda_offset(field))); \
> + break; \
> case 2: \
> asm(op "w %1,%%gs:%c2" \
> : "+m" (_proxy_pda.field) \
> @@ -41,6 +50,12 @@ extern struct i386_pda _proxy_pda;
> ({ \
> typeof(_proxy_pda.field) ret__; \
> switch (sizeof(_proxy_pda.field)) { \
> + case 1: \
> + asm(op "b %%gs:%c1,%0" \
> + : "=r" (ret__) \
> + : "i" (pda_offset(field)), \
> + "m" (_proxy_pda.field)); \
> + break; \
> case 2: \
> asm(op "w %%gs:%c1,%0" \
> : "=r" (ret__) \
> @@ -57,6 +72,10 @@ extern struct i386_pda _proxy_pda;
> } \
> ret__; })
>
> +/* Return a pointer to a pda field */
> +#define pda_addr(field) \
> + ((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \
> + pda_offset(field)))
I think i would prefer to merge that and the 1 byte one only
with actual users (x86-64 hasn't needed either for a long time)
-Andi
Andi Kleen wrote:
> I think i would prefer to merge that and the 1 byte one only
> with actual users (x86-64 hasn't needed either for a long time)
Taking the address of a PDA field is pretty useful. And it is going to
be important for a subsequent patch.
J
Andi Kleen wrote:
>> @@ -20,7 +22,14 @@ extern struct i386_pda _proxy_pda;
>> #define pda_to_op(op,field,val) \
>> do { \
>> typedef typeof(_proxy_pda.field) T__; \
>> + if (0) { T__ tmp__; tmp__ = (val); } \
>>
>
> Merged into original patch
>
BTW, do you mean you already had this in i386, or that you folded it
into the existing patch? I don't think I had sent out my version of
this before.
J
On Sat, Sep 09, 2006 at 04:30:31PM -0700, Jeremy Fitzhardinge wrote:
> Andi Kleen wrote:
> >>@@ -20,7 +22,14 @@ extern struct i386_pda _proxy_pda;
> >>#define pda_to_op(op,field,val) \
> >> do { \
> >> typedef typeof(_proxy_pda.field) T__; \
> >>+ if (0) { T__ tmp__; tmp__ = (val); } \
> >>
> >
> >Merged into original patch
> >
> BTW, do you mean you already had this in i386, or that you folded it
> into the existing patch? I don't think I had sent out my version of
> this before.
I folded it into the existing patch.
-Andi