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Subject[PATCH v3 2/6] powerpc/nohash: Convert set_context() to C
Date
ppc8xx already has set_context() in C.

Other ones have it in assembly. The only thing it does is to
write the context id into SPRN_PID.

Do it in C.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v3: Fixed whitespace before tab
---
arch/powerpc/include/asm/mmu_context.h | 1 -
arch/powerpc/kernel/head_40x.S | 7 -------
arch/powerpc/kernel/head_44x.S | 5 -----
arch/powerpc/kernel/head_fsl_booke.S | 5 -----
arch/powerpc/mm/nohash/8xx.c | 25 -------------------------
arch/powerpc/mm/nohash/mmu_context.c | 24 ++++++++++++++++++++++++
arch/powerpc/mm/nohash/tlb_low.S | 5 -----
7 files changed, 24 insertions(+), 48 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 4bc45d3ed8b0..ef6df2681582 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -57,7 +57,6 @@ static inline bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa,
static inline void mm_iommu_init(struct mm_struct *mm) { }
#endif
extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm);
-extern void set_context(unsigned long id, pgd_t *pgd);

#ifdef CONFIG_PPC_BOOK3S_64
extern void radix__switch_mmu_context(struct mm_struct *prev,
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 7ef1bbc23bed..2717aa860cae 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -702,13 +702,6 @@ _GLOBAL(abort)
oris r13,r13,DBCR0_RST_SYSTEM@h
mtspr SPRN_DBCR0,r13

-_GLOBAL(set_context)
- sync
- mtspr SPRN_PID,r3
- isync /* Need an isync to flush shadow */
- /* TLBs after changing PID */
- blr
-
/* We put a few things here that have to be page-aligned. This stuff
* goes at the beginning of the data segment, which is page-aligned.
*/
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index 57509d90e409..c5bec6a9864b 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -780,11 +780,6 @@ _GLOBAL(__fixup_440A_mcheck)
sync
blr

-_GLOBAL(set_context)
- mtspr SPRN_PID,r3
- isync /* Force context change */
- blr
-
/*
* Init CPU state. This is called at boot time or for secondary CPUs
* to setup initial TLB entries, setup IVORs, etc...
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 590f34cc5bb2..ab718fd5e2a2 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -985,11 +985,6 @@ _GLOBAL(abort)
mtspr SPRN_DBCR0,r13
isync

-_GLOBAL(set_context)
- mtspr SPRN_PID,r3
- isync /* Force context change */
- blr
-
#ifdef CONFIG_SMP
/* When we get here, r24 needs to hold the CPU # */
.globl __secondary_start
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index f749acba5473..65e4c8b92657 100644
--- a/arch/powerpc/mm/nohash/8xx.c
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -212,31 +212,6 @@ void __init setup_initial_memory_limit(phys_addr_t first_memblock_base,
memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_32M));
}

-/*
- * Set up to use a given MMU context.
- * id is context number, pgd is PGD pointer.
- *
- * We place the physical address of the new task page directory loaded
- * into the MMU base register, and set the ASID compare register with
- * the new "context."
- */
-void set_context(unsigned long id, pgd_t *pgd)
-{
- s16 offset = (s16)(__pa(swapper_pg_dir));
-
- /* Register M_TWB will contain base address of level 1 table minus the
- * lower part of the kernel PGDIR base address, so that all accesses to
- * level 1 table are done relative to lower part of kernel PGDIR base
- * address.
- */
- mtspr(SPRN_M_TWB, __pa(pgd) - offset);
-
- /* Update context */
- mtspr(SPRN_M_CASID, id - 1);
- /* sync */
- mb();
-}
-
#ifdef CONFIG_PPC_KUEP
void __init setup_kuep(bool disabled)
{
diff --git a/arch/powerpc/mm/nohash/mmu_context.c b/arch/powerpc/mm/nohash/mmu_context.c
index eae48635a9ac..75dafec50d19 100644
--- a/arch/powerpc/mm/nohash/mmu_context.c
+++ b/arch/powerpc/mm/nohash/mmu_context.c
@@ -264,6 +264,30 @@ static void context_check_map(void)
static void context_check_map(void) { }
#endif

+static void set_context(unsigned long id, pgd_t *pgd)
+{
+ if (IS_ENABLED(CONFIG_PPC_8xx)) {
+ s16 offset = (s16)(__pa(swapper_pg_dir));
+
+ /* Register M_TWB will contain base address of level 1 table minus the
+ * lower part of the kernel PGDIR base address, so that all accesses to
+ * level 1 table are done relative to lower part of kernel PGDIR base
+ * address.
+ */
+ mtspr(SPRN_M_TWB, __pa(pgd) - offset);
+
+ /* Update context */
+ mtspr(SPRN_M_CASID, id - 1);
+ /* sync */
+ mb();
+ } else {
+ if (IS_ENABLED(CONFIG_40x))
+ mb(); /* sync */
+ mtspr(SPRN_PID, id);
+ isync();
+ }
+}
+
void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
diff --git a/arch/powerpc/mm/nohash/tlb_low.S b/arch/powerpc/mm/nohash/tlb_low.S
index b3d0f0127828..4613bf8e9aae 100644
--- a/arch/powerpc/mm/nohash/tlb_low.S
+++ b/arch/powerpc/mm/nohash/tlb_low.S
@@ -360,11 +360,6 @@ _GLOBAL(_tlbivax_bcast)
sync
wrtee r10
blr
-
-_GLOBAL(set_context)
- mtspr SPRN_PID,r3
- isync /* Force context change */
- blr
#else
#error Unsupported processor type !
#endif
--
2.25.0
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