Commit 29e31da4 authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Will Deacon
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arm64/mm: Re-organise setting up FEAT_S1PIE registers PIRE0_EL1 and PIR_EL1 



mov_q cannot really move PIE_E[0|1] macros into a general purpose register
as expected if those macro constants contain some 128 bit layout elements,
that are required for D128 page tables. The primary issue is that for D128,
PIE_E[0|1] are defined in terms of 128-bit types with shifting and masking,
which the assembler can't accommodate.

Instead pre-calculate these PIRE0_EL1/PIR_EL1 constants into asm-offsets.h
based PIE_E0_ASM/PIE_E1_ASM which can then be used in arch/arm64/mm/proc.S.

While here also drop PTE_MAYBE_NG/PTE_MAYBE_SHARED assembly overrides which
are not required any longer, as the compiler toolchains are smart enough to
compute both the PIE_[E0|E1]_ASM constants in all scenarios.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: default avatarRyan Roberts <ryan.roberts@arm.com>
Link: https://lore.kernel.org/r/20250429050511.1663235-1-anshuman.khandual@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent c8597e2d

arch/arm64/kernel/asm-offsets.c

+2 −0
Original line number Diff line number Diff line
@@ -182,5 +182,7 @@ int main(void) 
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

  DEFINE(FTRACE_OPS_DIRECT_CALL,	offsetof(struct ftrace_ops, direct_call));

#endif

  DEFINE(PIE_E0_ASM, PIE_E0);

  DEFINE(PIE_E1_ASM, PIE_E1);

  return 0;

}

arch/arm64/mm/proc.S

+2 −17
Original line number Diff line number Diff line
@@ -512,26 +512,11 @@ alternative_else_nop_endif 
	ubfx	x1, x1, #ID_AA64MMFR3_EL1_S1PIE_SHIFT, #4

	cbz	x1, .Lskip_indirection



	/*

	 * The PROT_* macros describing the various memory types may resolve to

	 * C expressions if they include the PTE_MAYBE_* macros, and so they

	 * can only be used from C code. The PIE_E* constants below are also

	 * defined in terms of those macros, but will mask out those

	 * PTE_MAYBE_* constants, whether they are set or not. So #define them

	 * as 0x0 here so we can evaluate the PIE_E* constants in asm context.

	 */



#define PTE_MAYBE_NG		0

#define PTE_MAYBE_SHARED	0



	mov_q	x0, PIE_E0

	mov_q	x0, PIE_E0_ASM

	msr	REG_PIRE0_EL1, x0

	mov_q	x0, PIE_E1

	mov_q	x0, PIE_E1_ASM

	msr	REG_PIR_EL1, x0



#undef PTE_MAYBE_NG

#undef PTE_MAYBE_SHARED



	orr	tcr2, tcr2, TCR2_EL1_PIE

	msr	REG_TCR2_EL1, x0