linux/arch/riscv
Jinyu Tang 1b52861f0e
riscv: support update_mmu_tlb()
Add macro definition to support update_mmu_tlb() for riscv,
this function is from commit:7df676974359 ("mm/memory.c:Update
local TLB if PTE entry exists").

update_mmu_tlb() is used when a thread notice that other cpu thread
has handled the fault and changed the PTE. For MIPS, it's worth to
do that,this cpu thread will trap in tlb fault again otherwise.

For RISCV, it's also better to flush local tlb than do nothing in
update_mmu_tlb(). There are two kinds of page fault that have
update_mmu_tlb() inside:

1.page fault which PTE is NOT none, only protection check error,
like write protection fault. If updata_mmu_tlb() is empty, after
finsh page fault this time and re-execute, cpu will find address
but protection checked error in tlb again. So this will cause
another page fault. PTE in memory is good now,so update_mmu_cache()
in handle_pte_fault() will be executed. If updata_mmu_tlb() is not
empty flush local tlb, cpu won't find this address in tlb next time,
and get entry in physical memory, so it won't cause another page
fault.

2.page fault which PTE is none or swapped.
For this case, this cpu thread won't cause another page fault,cpu
will have tlb miss when re-execute, and get entry in memory
directly. But "set pte in phycial memory and flush local tlb" is
pratice in Linux, it's better to flush local tlb if it find entry
in phycial memory has changed.

Maybe it's same for other ARCH which can't detect PTE changed and
update it in local tlb automatically.

Signed-off-by: Jinyu Tang <tjytimi@163.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20221009134503.18783-1-tjytimi@163.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-10-28 12:43:02 -07:00
..
boot RISC-V Patches for the 6.1 Merge Window, Part 2 2022-10-14 11:21:11 -07:00
configs riscv: enable CD-ROM file systems in defconfig 2022-08-25 17:01:09 -07:00
errata drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores 2022-10-27 14:35:20 -07:00
include riscv: support update_mmu_tlb() 2022-10-28 12:43:02 -07:00
kernel RISC-V: Cache SBI vendor values 2022-10-27 14:35:11 -07:00
kvm The first batch of KVM patches, mostly covering x86, which I 2022-10-09 09:39:55 -07:00
lib riscv: lib: uaccess: fix CSR_STATUS SR_SUM bit 2022-08-10 14:06:31 -07:00
mm RISC-V Patches for the 6.1 Merge Window, Part 2 2022-10-14 11:21:11 -07:00
net bpf, riscv: Support riscv jit to provide bpf_line_info 2022-06-02 16:26:01 -07:00
purgatory riscv/purgatory: Omit use of bin2c 2022-08-11 09:32:34 -07:00
Kbuild riscv: move errata/ and kvm/ builds to arch/riscv/Kbuild 2022-06-01 22:26:32 -07:00
Kconfig RISC-V Patches for the 6.1 Merge Window, Part 2 2022-10-14 11:21:11 -07:00
Kconfig.debug RISC-V: Remove EARLY_PRINTK support 2018-12-17 10:23:46 -08:00
Kconfig.erratas drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores 2022-10-27 14:35:20 -07:00
Kconfig.socs riscv: Kconfig: Style cleanups 2022-06-30 19:26:16 -07:00
Makefile RISC-V Patches for the 6.1 Merge Window, Part 2 2022-10-14 11:21:11 -07:00