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Commit 609116d2 authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
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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: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Tested-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: default avatarJeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 86ccce89

arch/arm64/include/asm/mmu_context.h

+14 −2
Original line number Diff line number Diff line
@@ -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