riscv: mm: Introduce cntx2asid/cntx2version helper macros

When using the ASID allocator, the MM context ID contains two values:
the ASID in the lower bits, and the allocator version number in the
remaining bits. Use macros to make this separation more obvious.

Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240327045035.368512-10-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/include/asm/mmu.h b/arch/riscv/include/asm/mmu.h
index 355504b37f8ef2fdff87274590c9defdba2373a0..a550fbf770be2763bc58328ae58fea318b273947 100644 (file)
--- a/arch/riscv/include/asm/mmu.h
+++ b/arch/riscv/include/asm/mmu.h
@@ -26,6 +26,9 @@ typedef struct {
 #endif
 } mm_context_t;
 
+#define cntx2asid(cntx)                ((cntx) & asid_mask)
+#define cntx2version(cntx)     ((cntx) & ~asid_mask)
+
 void __init create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa,
                               phys_addr_t sz, pgprot_t prot);
 #endif /* __ASSEMBLY__ */

diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c
index ba8eb3944687cfd445770c357b32cb4fa0e37564..b562b3c444875a287130edcdf37bd81c2adaf057 100644 (file)
--- a/arch/riscv/mm/context.c
+++ b/arch/riscv/mm/context.c
@@ -81,7 +81,7 @@ static void __flush_context(void)
                if (cntx == 0)
                        cntx = per_cpu(reserved_context, i);
 
-               __set_bit(cntx & asid_mask, context_asid_map);
+               __set_bit(cntx2asid(cntx), context_asid_map);
                per_cpu(reserved_context, i) = cntx;
        }
 
@@ -102,7 +102,7 @@ static unsigned long __new_context(struct mm_struct *mm)
        lockdep_assert_held(&context_lock);
 
        if (cntx != 0) {
-               unsigned long newcntx = ver | (cntx & asid_mask);
+               unsigned long newcntx = ver | cntx2asid(cntx);
 
                /*
                 * If our current CONTEXT was active during a rollover, we
@@ -115,7 +115,7 @@ static unsigned long __new_context(struct mm_struct *mm)
                 * We had a valid CONTEXT in a previous life, so try to
                 * re-use it if possible.
                 */
-               if (!__test_and_set_bit(cntx & asid_mask, context_asid_map))
+               if (!__test_and_set_bit(cntx2asid(cntx), context_asid_map))
                        return newcntx;
        }
 
@@ -168,7 +168,7 @@ static void set_mm_asid(struct mm_struct *mm, unsigned int cpu)
         */
        old_active_cntx = atomic_long_read(&per_cpu(active_context, cpu));
        if (old_active_cntx &&
-           ((cntx & ~asid_mask) == atomic_long_read(&current_version)) &&
+           (cntx2version(cntx) == atomic_long_read(&current_version)) &&
            atomic_long_cmpxchg_relaxed(&per_cpu(active_context, cpu),
                                        old_active_cntx, cntx))
                goto switch_mm_fast;
@@ -177,7 +177,7 @@ static void set_mm_asid(struct mm_struct *mm, unsigned int cpu)
 
        /* Check that our ASID belongs to the current_version. */
        cntx = atomic_long_read(&mm->context.id);
-       if ((cntx & ~asid_mask) != atomic_long_read(&current_version)) {
+       if (cntx2version(cntx) != atomic_long_read(&current_version)) {
                cntx = __new_context(mm);
                atomic_long_set(&mm->context.id, cntx);
        }
@@ -191,7 +191,7 @@ static void set_mm_asid(struct mm_struct *mm, unsigned int cpu)
 
 switch_mm_fast:
        csr_write(CSR_SATP, virt_to_pfn(mm->pgd) |
-                 ((cntx & asid_mask) << SATP_ASID_SHIFT) |
+                 (cntx2asid(cntx) << SATP_ASID_SHIFT) |
                  satp_mode);
 
        if (need_flush_tlb)

diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index 18af7b5053af232a645b0836887daf6ea9af5035..35266dd9a9a2cca5a9a8b7780d6659eb74456d10 100644 (file)
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -110,7 +110,7 @@ static void __flush_tlb_range(struct cpumask *cmask, unsigned long asid,
 static inline unsigned long get_mm_asid(struct mm_struct *mm)
 {
        return static_branch_unlikely(&use_asid_allocator) ?
-                       atomic_long_read(&mm->context.id) & asid_mask : FLUSH_TLB_NO_ASID;
+                       cntx2asid(atomic_long_read(&mm->context.id)) : FLUSH_TLB_NO_ASID;
 }
 
 void flush_tlb_mm(struct mm_struct *mm)