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riscv: Apply SiFive CIP-1200 workaround to single-ASID sfence.vma

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[ Upstream commit 20e03d702e ]

commit 3f1e782998 ("riscv: add ASID-based tlbflushing methods") added
calls to the sfence.vma instruction with rs2 != x0. These single-ASID
instruction variants are also affected by SiFive errata CIP-1200.

Until now, the errata workaround was not needed for the single-ASID
sfence.vma variants, because they were only used when the ASID allocator
was enabled, and the affected SiFive platforms do not support multiple
ASIDs. However, we are going to start using those sfence.vma variants
regardless of ASID support, so now we need alternatives covering them.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240327045035.368512-8-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Samuel Holland 2024-03-26 21:49:48 -07:00 committed by Greg Kroah-Hartman
parent af19067bd5
commit 864a024250
3 changed files with 29 additions and 25 deletions
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12
arch/riscv/include/asm/errata_list.h
View File

@ -44,11 +44,21 @@ ALTERNATIVE(__stringify(RISCV_PTR do_page_fault), \
CONFIG_ERRATA_SIFIVE_CIP_453)
#else /* !__ASSEMBLY__ */
#define ALT_FLUSH_TLB_PAGE(x) \
#define ALT_SFENCE_VMA_ASID(asid) \
asm(ALTERNATIVE("sfence.vma x0, %0", "sfence.vma", SIFIVE_VENDOR_ID, \
ERRATA_SIFIVE_CIP_1200, CONFIG_ERRATA_SIFIVE_CIP_1200) \
: : "r" (asid) : "memory")
#define ALT_SFENCE_VMA_ADDR(addr) \
asm(ALTERNATIVE("sfence.vma %0", "sfence.vma", SIFIVE_VENDOR_ID, \
ERRATA_SIFIVE_CIP_1200, CONFIG_ERRATA_SIFIVE_CIP_1200) \
: : "r" (addr) : "memory")
#define ALT_SFENCE_VMA_ADDR_ASID(addr, asid) \
asm(ALTERNATIVE("sfence.vma %0, %1", "sfence.vma", SIFIVE_VENDOR_ID, \
ERRATA_SIFIVE_CIP_1200, CONFIG_ERRATA_SIFIVE_CIP_1200) \
: : "r" (addr), "r" (asid) : "memory")
/*
* _val is marked as "will be overwritten", so need to set it to 0
* in the default case.

19
arch/riscv/include/asm/tlbflush.h
View File

@ -22,10 +22,27 @@ static inline void local_flush_tlb_all(void)
__asm__ __volatile__ ("sfence.vma" : : : "memory");
}
static inline void local_flush_tlb_all_asid(unsigned long asid)
{
if (asid != FLUSH_TLB_NO_ASID)
ALT_SFENCE_VMA_ASID(asid);
else
local_flush_tlb_all();
}
/* Flush one page from local TLB */
static inline void local_flush_tlb_page(unsigned long addr)
{
ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory"));
ALT_SFENCE_VMA_ADDR(addr);
}
static inline void local_flush_tlb_page_asid(unsigned long addr,
unsigned long asid)
{
if (asid != FLUSH_TLB_NO_ASID)
ALT_SFENCE_VMA_ADDR_ASID(addr, asid);
else
local_flush_tlb_page(addr);
}
#else /* CONFIG_MMU */
#define local_flush_tlb_all() do { } while (0)

23
arch/riscv/mm/tlbflush.c
View File

@ -6,29 +6,6 @@
#include <asm/sbi.h>
#include <asm/mmu_context.h>
static inline void local_flush_tlb_all_asid(unsigned long asid)
{
if (asid != FLUSH_TLB_NO_ASID)
__asm__ __volatile__ ("sfence.vma x0, %0"
:
: "r" (asid)
: "memory");
else
local_flush_tlb_all();
}
static inline void local_flush_tlb_page_asid(unsigned long addr,
unsigned long asid)
{
if (asid != FLUSH_TLB_NO_ASID)
__asm__ __volatile__ ("sfence.vma %0, %1"
:
: "r" (addr), "r" (asid)
: "memory");
else
local_flush_tlb_page(addr);
}
/*
* Flush entire TLB if number of entries to be flushed is greater
* than the threshold below.