Commit af7249b3 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Catalin Marinas
Browse files

arm64: kernel: move identity map out of .text mapping 



Reorganize the ID map slightly so that only code that is executed with
the MMU off or via the 1:1 mapping remains. This allows us to move the
identity map out of the .text segment, as it will no longer need
executable permissions via the kernel mapping.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230111102236.1430401-3-ardb@kernel.org


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 82e49588

arch/arm64/kernel/head.S

+15 −13
Original line number Diff line number Diff line
@@ -543,19 +543,6 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) 
	eret

SYM_FUNC_END(init_kernel_el)



/*

 * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed

 * in w0. See arch/arm64/include/asm/virt.h for more info.

 */

SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag)

	adr_l	x1, __boot_cpu_mode

	cmp	w0, #BOOT_CPU_MODE_EL2

	b.ne	1f

	add	x1, x1, #4

1:	str	w0, [x1]			// Save CPU boot mode

	ret

SYM_FUNC_END(set_cpu_boot_mode_flag)



	/*

	 * This provides a "holding pen" for platforms to hold all secondary

	 * cores are held until we're ready for them to initialise.
@@ -599,6 +586,7 @@ SYM_FUNC_START_LOCAL(secondary_startup) 
	br	x8

SYM_FUNC_END(secondary_startup)



	.text

SYM_FUNC_START_LOCAL(__secondary_switched)

	mov	x0, x20

	bl	set_cpu_boot_mode_flag
@@ -631,6 +619,19 @@ SYM_FUNC_START_LOCAL(__secondary_too_slow) 
	b	__secondary_too_slow

SYM_FUNC_END(__secondary_too_slow)



/*

 * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed

 * in w0. See arch/arm64/include/asm/virt.h for more info.

 */

SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag)

	adr_l	x1, __boot_cpu_mode

	cmp	w0, #BOOT_CPU_MODE_EL2

	b.ne	1f

	add	x1, x1, #4

1:	str	w0, [x1]			// Save CPU boot mode

	ret

SYM_FUNC_END(set_cpu_boot_mode_flag)



/*

 * The booting CPU updates the failed status @__early_cpu_boot_status,

 * with MMU turned off.
@@ -662,6 +663,7 @@ SYM_FUNC_END(__secondary_too_slow) 
 * Checks if the selected granule size is supported by the CPU.

 * If it isn't, park the CPU

 */

	.section ".idmap.text","awx"

SYM_FUNC_START(__enable_mmu)

	mrs	x3, ID_AA64MMFR0_EL1

	ubfx	x3, x3, #ID_AA64MMFR0_EL1_TGRAN_SHIFT, 4

arch/arm64/kernel/vmlinux.lds.S

+1 −1
Original line number Diff line number Diff line
@@ -179,7 +179,6 @@ SECTIONS 
			LOCK_TEXT

			KPROBES_TEXT

			HYPERVISOR_TEXT

			IDMAP_TEXT

			*(.gnu.warning)

		. = ALIGN(16);

		*(.got)			/* Global offset table		*/
@@ -206,6 +205,7 @@ SECTIONS 
		TRAMP_TEXT

		HIBERNATE_TEXT

		KEXEC_TEXT

		IDMAP_TEXT

		. = ALIGN(PAGE_SIZE);

	}

arch/arm64/mm/proc.S

+0 −2
Original line number Diff line number Diff line
@@ -110,7 +110,6 @@ SYM_FUNC_END(cpu_do_suspend) 
 *

 * x0: Address of context pointer

 */

	.pushsection ".idmap.text", "awx"

SYM_FUNC_START(cpu_do_resume)

	ldp	x2, x3, [x0]

	ldp	x4, x5, [x0, #16]
@@ -166,7 +165,6 @@ alternative_else_nop_endif 
	isb

	ret

SYM_FUNC_END(cpu_do_resume)

	.popsection

#endif



	.pushsection ".idmap.text", "awx"