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arm64: add function to install the idmap 

In some cases (e.g. when making invasive changes to the kernel page
tables) we will need to execute code from the idmap.

Add a new helper which may be used to install the idmap, complementing
the existing cpu_uninstall_idmap.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2016-01-25 11:45:00 +00:00 committed by Catalin Marinas
parent 86ccce896c
commit 609116d202
1 changed files with 14 additions and 2 deletions
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16
arch/arm64/include/asm/mmu_context.h
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@ -74,7 +74,7 @@ static inline bool __cpu_uses_extended_idmap(void)
/*
* Set TCR.T0SZ to its default value (based on VA_BITS)
*/
static inline void cpu_set_default_tcr_t0sz(void)
static inline void __cpu_set_tcr_t0sz(unsigned long t0sz)
{
unsigned long tcr;
@ -87,9 +87,12 @@ static inline void cpu_set_default_tcr_t0sz(void)
" msr tcr_el1, %0 ;"
" isb"
: "=&r" (tcr)
: "r"(TCR_T0SZ(VA_BITS)), "I"(TCR_T0SZ_OFFSET), "I"(TCR_TxSZ_WIDTH));
: "r"(t0sz), "I"(TCR_T0SZ_OFFSET), "I"(TCR_TxSZ_WIDTH));
}
#define cpu_set_default_tcr_t0sz() __cpu_set_tcr_t0sz(TCR_T0SZ(VA_BITS))
#define cpu_set_idmap_tcr_t0sz() __cpu_set_tcr_t0sz(idmap_t0sz)
/*
* Remove the idmap from TTBR0_EL1 and install the pgd of the active mm.
*
@ -114,6 +117,15 @@ static inline void cpu_uninstall_idmap(void)
cpu_switch_mm(mm->pgd, mm);
}
static inline void cpu_install_idmap(void)
{
cpu_set_reserved_ttbr0();
local_flush_tlb_all();
cpu_set_idmap_tcr_t0sz();
cpu_switch_mm(idmap_pg_dir, &init_mm);
}
/*
* It would be nice to return ASIDs back to the allocator, but unfortunately
* that introduces a race with a generation rollover where we could erroneously