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| author | Mark Rutland <mark.rutland@arm.com> | 2020-02-13 12:14:52 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-02-27 14:30:50 +0000 |
| commit | 25b92693a1b67a47b0c64a3410009d09e9658412 (patch) | |
| tree | 6a976dc413dc64669b6ba2a4b61ef571b21c1a88 /arch/arm64/mm/context.c | |
| parent | 4399e6cdf3e920ab99c5f935ecbae88e60682596 (diff) | |
| download | linux-25b92693a1b67a47b0c64a3410009d09e9658412.tar.bz2 | |
arm64: mm: convert cpu_do_switch_mm() to C
There's no reason that cpu_do_switch_mm() needs to be written as an
assembly function, and having it as a C function would make it easier to
maintain.
This patch converts cpu_do_switch_mm() to C, removing code that this
change makes redundant (e.g. the mmid macro). Since the header comment
was stale and the prototype now implies all the necessary information,
this comment is removed. The 'pgd_phys' argument is made a phys_addr_t
to match the return type of virt_to_phys().
At the same time, post_ttbr_update_workaround() is updated to use
IS_ENABLED(), which allows the compiler to figure out it can elide calls
for !CONFIG_CAVIUM_ERRATUM_27456 builds.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
[catalin.marinas@arm.com: change comments from asm-style to C-style]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm/context.c')
| -rw-r--r-- | arch/arm64/mm/context.c | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c index 8ef73e89d514..8524f03d629c 100644 --- a/arch/arm64/mm/context.c +++ b/arch/arm64/mm/context.c @@ -6,6 +6,7 @@ * Copyright (C) 2012 ARM Ltd. */ +#include <linux/bitfield.h> #include <linux/bitops.h> #include <linux/sched.h> #include <linux/slab.h> @@ -254,10 +255,37 @@ switch_mm_fastpath: /* Errata workaround post TTBRx_EL1 update. */ asmlinkage void post_ttbr_update_workaround(void) { + if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) + return; + asm(ALTERNATIVE("nop; nop; nop", "ic iallu; dsb nsh; isb", - ARM64_WORKAROUND_CAVIUM_27456, - CONFIG_CAVIUM_ERRATUM_27456)); + ARM64_WORKAROUND_CAVIUM_27456)); +} + +void cpu_do_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm) +{ + unsigned long ttbr1 = read_sysreg(ttbr1_el1); + unsigned long asid = ASID(mm); + unsigned long ttbr0 = phys_to_ttbr(pgd_phys); + + /* Skip CNP for the reserved ASID */ + if (system_supports_cnp() && asid) + ttbr0 |= TTBR_CNP_BIT; + + /* SW PAN needs a copy of the ASID in TTBR0 for entry */ + if (IS_ENABLED(CONFIG_ARM64_SW_TTBR0_PAN)) + ttbr0 |= FIELD_PREP(TTBR_ASID_MASK, asid); + + /* Set ASID in TTBR1 since TCR.A1 is set */ + ttbr1 &= ~TTBR_ASID_MASK; + ttbr1 |= FIELD_PREP(TTBR_ASID_MASK, asid); + + write_sysreg(ttbr1, ttbr1_el1); + isb(); + write_sysreg(ttbr0, ttbr0_el1); + isb(); + post_ttbr_update_workaround(); } static int asids_init(void) |