Benjamin Herrenschmidt <b...@kernel.crashing.org> writes:
> On Wed, 2013-02-13 at 08:54 +0530, Aneesh Kumar K.V wrote:
>> > A compile option ? Really ? Ugh...
>>
>> I actually wanted that to be done in Kconfig.cputype, but haven't found
>> a nice way to do it. Considering we are switching between only two
>> values, I was thinking an #ifdef would work.
>
> No, we want to support all those processor types from a single kernel image.
Ok. How about the below patch. This is based on the suggestion from
Paulus. I still have to take care of few comments in the code.
We now split the proto-vsid range differently.
User: 0 to [2^(CONTEXT_BITS) - 4 + 2^(USER_ESID_BITS)]
kernel: [2^(CONTEXT_BITS) - 4 + 2^(USER_ESID_BITS)] to 2^(VSID_BITS) - 1
Phileas and Geoff,
Can we check whether this fix the PS3 boot hang ?
-aneesh
diff --git a/arch/powerpc/include/asm/mmu-hash64.h
b/arch/powerpc/include/asm/mmu-hash64.h
index 2fdb47a..1e65a01 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -381,21 +381,33 @@ extern void slb_set_size(u16 size);
* hash collisions.
*/
+#define CONTEXT_BITS 19
+#define USER_ESID_BITS 18
+#define USER_ESID_BITS_1T 6
+
+/*
+ * 256MB segment
+ * The proto-VSID space has 2^(CONTEX_BITS + USER_ESID_BITS) - 1 segments
+ * available for user + kernel mapping. The top 4 contexts are used for
+ * kernel mapping. Each segment contains 2^28 bytes. Each
+ * context maps 2^46 bytes (64TB) so we can support 2^19-1 contexts
+ * (19 == 37 + 28 - 46).
+ */
+#define MAX_CONTEXT ((ASM_CONST(1) << CONTEXT_BITS) - 1)
+
+
/*
* This should be computed such that protovosid * vsid_mulitplier
* doesn't overflow 64 bits. It should also be co-prime to vsid_modulus
*/
#define VSID_MULTIPLIER_256M ASM_CONST(12538073) /* 24-bit prime */
-#define VSID_BITS_256M 38
+#define VSID_BITS_256M (CONTEXT_BITS + USER_ESID_BITS)
#define VSID_MODULUS_256M ((1UL<<VSID_BITS_256M)-1)
#define VSID_MULTIPLIER_1T ASM_CONST(12538073) /* 24-bit prime */
-#define VSID_BITS_1T 26
+#define VSID_BITS_1T (CONTEXT_BITS + USER_ESID_BITS_1T)
#define VSID_MODULUS_1T ((1UL<<VSID_BITS_1T)-1)
-#define CONTEXT_BITS 19
-#define USER_ESID_BITS 18
-#define USER_ESID_BITS_1T 6
#define USER_VSID_RANGE (1UL << (USER_ESID_BITS + SID_SHIFT))
@@ -513,34 +525,6 @@ typedef struct {
})
#endif /* 1 */
-/*
- * This is only valid for addresses >= PAGE_OFFSET
- * The proto-VSID space is divided into two class
- * User: 0 to 2^(CONTEXT_BITS + USER_ESID_BITS) -1
- * kernel: 2^(CONTEXT_BITS + USER_ESID_BITS) to 2^(VSID_BITS) - 1
- *
- * With KERNEL_START at 0xc000000000000000, the proto vsid for
- * the kernel ends up with 0xc00000000 (36 bits). With 64TB
- * support we need to have kernel proto-VSID in the
- * [2^37 to 2^38 - 1] range due to the increased USER_ESID_BITS.
- */
-static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
-{
- unsigned long proto_vsid;
- /*
- * We need to make sure proto_vsid for the kernel is
- * >= 2^(CONTEXT_BITS + USER_ESID_BITS[_1T])
- */
- if (ssize == MMU_SEGSIZE_256M) {
- proto_vsid = ea >> SID_SHIFT;
- proto_vsid |= (1UL << (CONTEXT_BITS + USER_ESID_BITS));
- return vsid_scramble(proto_vsid, 256M);
- }
- proto_vsid = ea >> SID_SHIFT_1T;
- proto_vsid |= (1UL << (CONTEXT_BITS + USER_ESID_BITS_1T));
- return vsid_scramble(proto_vsid, 1T);
-}
-
/* Returns the segment size indicator for a user address */
static inline int user_segment_size(unsigned long addr)
{
@@ -561,6 +545,26 @@ static inline unsigned long get_vsid(unsigned long
context, unsigned long ea,
| (ea >> SID_SHIFT_1T), 1T);
}
+/*
+ * This is only valid for addresses >= PAGE_OFFSET
+ * The proto-VSID space is divided into two class
+ * User: 0 to 2^(CONTEXT_BITS) - 4 + 2^(USER_ESID_BITS)
+ * kernel: 2^(CONTEXT_BITS) - 4 + 2^(USER_ESID_BITS) to 2^(VSID_BITS) - 1
+ *
+ * With KERNEL_START at 0xc000000000000000, the proto vsid for
+ * the kernel ends up with 0xc00000000 (36 bits). We use one context
+ * for 0xc, 0xd, 0xe and 0xf.
+ *
+ */
+static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
+{
+ unsigned long context;
+ /*
+ * kernel take the top 4 context from the available range
+ */
+ context = (MAX_CONTEXT - 4) + ((ea >> 60) - 0xc);
+ return get_vsid(context, ea, ssize);
+}
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_MMU_HASH64_H_ */
diff --git a/arch/powerpc/kernel/exceptions-64s.S
b/arch/powerpc/kernel/exceptions-64s.S
index 4665e82..78c6d0b 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1269,16 +1269,23 @@ _GLOBAL(do_stab_bolted)
stw r9,PACA_EXSLB+EX_CCR(r13) /* save CR in exc. frame */
std r11,PACA_EXSLB+EX_SRR0(r13) /* save SRR0 in exc. frame */
+ mfspr r11,SPRN_DAR
+ srdi r9,r11,60 /* ea >> 60 */
+ srdi r11,r11,SID_SHIFT
+
+ /* Calculate VSID:
+ * This is the kernel vsid, we take the top for context from
+ * the range. context = (MAX_CONTEXT - 4) + ((ea >> 60) - 0xc)
+ */
+ subi r9,r9,(0xc + 4 + 1)
+ lis r10,8
+ add r9,r9,r10
+
/* Hash to the primary group */
ld r10,PACASTABVIRT(r13)
- mfspr r11,SPRN_DAR
- srdi r11,r11,28
rldimi r10,r11,7,52 /* r10 = first ste of the group */
+ rldimi r11,r9,USER_ESID_BITS,0 /* proto vsid */
- /* Calculate VSID */
- /* This is a kernel address, so protovsid = ESID | 1 << 37 */
- li r9,0x1
- rldimi r11,r9,(CONTEXT_BITS + USER_ESID_BITS),0
ASM_VSID_SCRAMBLE(r11, r9, 256M)
rldic r9,r11,12,16 /* r9 = vsid << 12 */
diff --git a/arch/powerpc/mm/mmu_context_hash64.c
b/arch/powerpc/mm/mmu_context_hash64.c
index 40bc5b0..9c84b16 100644
--- a/arch/powerpc/mm/mmu_context_hash64.c
+++ b/arch/powerpc/mm/mmu_context_hash64.c
@@ -29,15 +29,6 @@
static DEFINE_SPINLOCK(mmu_context_lock);
static DEFINE_IDA(mmu_context_ida);
-/*
- * 256MB segment
- * The proto-VSID space has 2^(CONTEX_BITS + USER_ESID_BITS) - 1 segments
- * available for user mappings. Each segment contains 2^28 bytes. Each
- * context maps 2^46 bytes (64TB) so we can support 2^19-1 contexts
- * (19 == 37 + 28 - 46).
- */
-#define MAX_CONTEXT ((1UL << CONTEXT_BITS) - 1)
-
int __init_new_context(void)
{
int index;
@@ -56,7 +47,7 @@ again:
else if (err)
return err;
- if (index > MAX_CONTEXT) {
+ if (index > (MAX_CONTEXT - 4)) {
spin_lock(&mmu_context_lock);
ida_remove(&mmu_context_ida, index);
spin_unlock(&mmu_context_lock);
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
index 1a16ca2..487f998 100644
--- a/arch/powerpc/mm/slb_low.S
+++ b/arch/powerpc/mm/slb_low.S
@@ -56,12 +56,19 @@ _GLOBAL(slb_allocate_realmode)
*/
_GLOBAL(slb_miss_kernel_load_linear)
li r11,0
- li r9,0x1
+ /*
+ * context = (MAX_CONTEXT - 4) + ((ea >> 60) - 0xc)
+ */
+ srdi r9,r3,60
+ subi r9,r9,(0xc + 4 + 1)
+ lis r10, 8
+ add r9,r9,r10
+ srdi r10,r3,28 /* FIXME!! doing it twice */
/*
* for 1T we shift 12 bits more. slb_finish_load_1T will do
* the necessary adjustment
*/
- rldimi r10,r9,(CONTEXT_BITS + USER_ESID_BITS),0
+ rldimi r10,r9,USER_ESID_BITS,0
BEGIN_FTR_SECTION
b slb_finish_load
END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
@@ -91,12 +98,19 @@ _GLOBAL(slb_miss_kernel_load_vmemmap)
_GLOBAL(slb_miss_kernel_load_io)
li r11,0
6:
- li r9,0x1
+ /*
+ * context = (MAX_CONTEXT - 4) + ((ea >> 60) - 0xc)
+ */
+ srdi r9,r3,60
+ subi r9,r9,(0xc + 4 + 1)
+ lis r10,8
+ add r9,r9,r10
+ srdi r10,r3,28 /* FIXME!! doing it twice */
/*
* for 1T we shift 12 bits more. slb_finish_load_1T will do
* the necessary adjustment
*/
- rldimi r10,r9,(CONTEXT_BITS + USER_ESID_BITS),0
+ rldimi r10,r9,USER_ESID_BITS,0
BEGIN_FTR_SECTION
b slb_finish_load
END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
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