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riscv: mm: Add support for Svinval extension

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The Svinval extension splits SFENCE.VMA instruction into finer-grained
invalidation and ordering operations and is mandatory for RVA23S64 profile.
When Svinval is enabled the local_flush_tlb_range_threshold_asid function
should use the following sequence to optimize the tlb flushes instead of
a simple sfence.vma:

sfence.w.inval
svinval.vma
  .
  .
svinval.vma
sfence.inval.ir

The maximum number of consecutive svinval.vma instructions that
can be executed in local_flush_tlb_range_threshold_asid function
is limited to 64. This is required to avoid soft lockups and the
approach is similar to that used in arm64.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240702102637.9074-1-mchitale@ventanamicro.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
This commit is contained in:
Mayuresh Chitale 2024-07-02 15:56:37 +05:30 • committed by Palmer Dabbelt
parent 82f2b0b97b
commit a569726988
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1 changed files with 31 additions and 0 deletions
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31
arch/riscv/mm/tlbflush.c
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@ -7,6 +7,27 @@
#include <linux/mmu_notifier.h>
#include <asm/sbi.h>
#include <asm/mmu_context.h>
#include <asm/cpufeature.h>
#define has_svinval() riscv_has_extension_unlikely(RISCV_ISA_EXT_SVINVAL)
static inline void local_sfence_inval_ir(void)
{
asm volatile(SFENCE_INVAL_IR() ::: "memory");
}
static inline void local_sfence_w_inval(void)
{
asm volatile(SFENCE_W_INVAL() ::: "memory");
}
static inline void local_sinval_vma(unsigned long vma, unsigned long asid)
{
if (asid != FLUSH_TLB_NO_ASID)
asm volatile(SINVAL_VMA(%0, %1) : : "r" (vma), "r" (asid) : "memory");
else
asm volatile(SINVAL_VMA(%0, zero) : : "r" (vma) : "memory");
}
/*
* Flush entire TLB if number of entries to be flushed is greater
@ -27,6 +48,16 @@ static void local_flush_tlb_range_threshold_asid(unsigned long start,
return;
}
if (has_svinval()) {
local_sfence_w_inval();
for (i = 0; i < nr_ptes_in_range; ++i) {
local_sinval_vma(start, asid);
start += stride;
}
local_sfence_inval_ir();
return;
}
for (i = 0; i < nr_ptes_in_range; ++i) {
local_flush_tlb_page_asid(start, asid);
start += stride;