diff options
| author | Vineet Gupta | 2014-11-13 19:27:24 +0530 |
|---|---|---|
| committer | Vineet Gupta | 2019-10-28 12:12:31 -0700 |
| commit | cfd9d70a855edf6adb37d0ed88be9e35274dbe49 (patch) | |
| tree | 3be75666a3101764e58a227672dbf5e25f945da4 /arch/arc/include | |
| parent | 7b491c0b62594a21cab357e0118603830a500de3 (diff) | |
ARCv2: mm: TLB Miss optim: SMP builds can cache pgd pointer in mmu scratch reg
ARC700 exception (and intr handling) didn't have auto stack switching
thus had to rely on stashing a reg temporarily (to free it up) at a
known place in memory, allowing to code up the low level stack switching.
This however was not re-entrant in SMP which thus had to repurpose the
per-cpu MMU SCRATCH DATA register otherwise used to "cache" the task pdg
pointer (vs. reading it from mm struct)
The newer HS cores do have auto-stack switching and thus even SMP builds
can use the MMU SCRATCH reg as originally intended.
This patch fixes the restriction to ARC700 SMP builds only
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/include')
| -rw-r--r-- | arch/arc/include/asm/entry-compact.h | 4 | ||||
| -rw-r--r-- | arch/arc/include/asm/mmu.h | 4 | ||||
| -rw-r--r-- | arch/arc/include/asm/mmu_context.h | 2 | ||||
| -rw-r--r-- | arch/arc/include/asm/pgtable.h | 2 |
4 files changed, 8 insertions, 4 deletions
diff --git a/arch/arc/include/asm/entry-compact.h b/arch/arc/include/asm/entry-compact.h index 66a292335ee6..c3aa775878dc 100644 --- a/arch/arc/include/asm/entry-compact.h +++ b/arch/arc/include/asm/entry-compact.h @@ -130,7 +130,7 @@ * to be saved again on kernel mode stack, as part of pt_regs. *-------------------------------------------------------------*/ .macro PROLOG_FREEUP_REG reg, mem -#ifdef CONFIG_SMP +#ifndef ARC_USE_SCRATCH_REG sr \reg, [ARC_REG_SCRATCH_DATA0] #else st \reg, [\mem] @@ -138,7 +138,7 @@ .endm .macro PROLOG_RESTORE_REG reg, mem -#ifdef CONFIG_SMP +#ifndef ARC_USE_SCRATCH_REG lr \reg, [ARC_REG_SCRATCH_DATA0] #else ld \reg, [\mem] diff --git a/arch/arc/include/asm/mmu.h b/arch/arc/include/asm/mmu.h index 98cadf1a09ac..0abacb82a72b 100644 --- a/arch/arc/include/asm/mmu.h +++ b/arch/arc/include/asm/mmu.h @@ -40,6 +40,10 @@ #define ARC_REG_SCRATCH_DATA0 0x46c #endif +#if defined(CONFIG_ISA_ARCV2) || !defined(CONFIG_SMP) +#define ARC_USE_SCRATCH_REG +#endif + /* Bits in MMU PID register */ #define __TLB_ENABLE (1 << 31) #define __PROG_ENABLE (1 << 30) diff --git a/arch/arc/include/asm/mmu_context.h b/arch/arc/include/asm/mmu_context.h index 035470816be5..3a5e6a5b9ed6 100644 --- a/arch/arc/include/asm/mmu_context.h +++ b/arch/arc/include/asm/mmu_context.h @@ -144,7 +144,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, */ cpumask_set_cpu(cpu, mm_cpumask(next)); -#ifndef CONFIG_SMP +#ifdef ARC_USE_SCRATCH_REG /* PGD cached in MMU reg to avoid 3 mem lookups: task->mm->pgd */ write_aux_reg(ARC_REG_SCRATCH_DATA0, next->pgd); #endif diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index 7addd0301c51..ea14a8bfc691 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -351,7 +351,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, * Thus use this macro only when you are certain that "current" is current * e.g. when dealing with signal frame setup code etc */ -#ifndef CONFIG_SMP +#ifdef ARC_USE_SCRATCH_REG #define pgd_offset_fast(mm, addr) \ ({ \ pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0); \ |