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: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230111102236.1430401-3-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index c4e12d466a5f35f0b73b73d320db52fd6a019868..bec97aad092c2b43f6b0ffc2ede5ffb5760124a8 100644 (file)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -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

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 4c13dafc98b8400f51468c880a2513242b65b669..407415a5163ab62f2ba2893d4004b8679342af6a 100644 (file)
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -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);
        }
 

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 066fa60b93d24827f7164fb89efc8079e0b0b2e9..91410f48809000a0af4e36578cb862ad4d12f1ab 100644 (file)
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -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"