From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 4/9] arm64: head.S: move KASLR processing out of __enable_mmu()
Date: Wed, 24 Aug 2016 16:36:01 +0200 [thread overview]
Message-ID: <1472049366-10922-5-git-send-email-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <1472049366-10922-1-git-send-email-ard.biesheuvel@linaro.org>
The KASLR processing in __enable_mmu() is only used by the primary boot
path, and complements the processing that takes place in __primary_switch().
Move the two parts together, to make the code easier to understand.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/arm64/kernel/head.S | 66 ++++++++++++--------
1 file changed, 39 insertions(+), 27 deletions(-)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 2871271123e7..d390feb92730 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -222,9 +222,7 @@ ENTRY(stext)
* the TCR will have been set.
*/
bl __cpu_setup // initialise processor
- adr_l x27, __primary_switch // address to jump to after
- // MMU has been enabled
- b __enable_mmu
+ b __primary_switch
ENDPROC(stext)
/*
@@ -453,7 +451,7 @@ __primary_switched:
cbz x0, 0f // KASLR disabled? just proceed
orr x23, x23, x0 // record KASLR offset
ret x28 // we must enable KASLR, return
- // to __enable_mmu()
+ // to __primary_switch()
0:
#endif
b start_kernel
@@ -721,7 +719,6 @@ ENTRY(__early_cpu_boot_status)
*/
.section ".idmap.text", "ax"
ENTRY(__enable_mmu)
- mrs x22, sctlr_el1 // preserve old SCTLR_EL1 value
mrs x1, ID_AA64MMFR0_EL1
ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4
cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED
@@ -742,25 +739,6 @@ ENTRY(__enable_mmu)
ic iallu
dsb nsh
isb
-#ifdef CONFIG_RANDOMIZE_BASE
- mov x19, x0 // preserve new SCTLR_EL1 value
- blr x27
-
- /*
- * If we return here, we have a KASLR displacement in x23 which we need
- * to take into account by discarding the current kernel mapping and
- * creating a new one.
- */
- msr sctlr_el1, x22 // disable the MMU
- isb
- bl __create_page_tables // recreate kernel mapping
-
- msr sctlr_el1, x19 // re-enable the MMU
- isb
- ic iallu // flush instructions fetched
- dsb nsh // via old mapping
- isb
-#endif
br x27
ENDPROC(__enable_mmu)
@@ -770,11 +748,11 @@ __no_granule_support:
1:
wfe
wfi
- b 1b
+ b 1b
ENDPROC(__no_granule_support)
-__primary_switch:
#ifdef CONFIG_RELOCATABLE
+__relocate_kernel:
/*
* Iterate over each entry in the relocation table, and apply the
* relocations in place.
@@ -796,8 +774,42 @@ __primary_switch:
add x13, x13, x23 // relocate
str x13, [x11, x23]
b 0b
+1: ret
+ENDPROC(__relocate_kernel)
+#endif
-1:
+__primary_switch:
+#ifdef CONFIG_RANDOMIZE_BASE
+ mov x19, x0 // preserve new SCTLR_EL1 value
+ mrs x20, sctlr_el1 // preserve old SCTLR_EL1 value
+#endif
+
+ adr x27, 0f
+ b __enable_mmu
+0:
+#ifdef CONFIG_RELOCATABLE
+ bl __relocate_kernel
+#ifdef CONFIG_RANDOMIZE_BASE
+ ldr x8, =__primary_switched
+ blr x8
+
+ /*
+ * If we return here, we have a KASLR displacement in x23 which we need
+ * to take into account by discarding the current kernel mapping and
+ * creating a new one.
+ */
+ msr sctlr_el1, x20 // disable the MMU
+ isb
+ bl __create_page_tables // recreate kernel mapping
+
+ msr sctlr_el1, x19 // re-enable the MMU
+ isb
+ ic iallu // flush instructions fetched
+ dsb nsh // via old mapping
+ isb
+
+ bl __relocate_kernel
+#endif
#endif
ldr x8, =__primary_switched
br x8
--
2.7.4
next prev parent reply other threads:[~2016-08-24 14:36 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-24 14:35 [PATCH v2 0/9] arm64: clean up early boot function calls Ard Biesheuvel
2016-08-24 14:35 ` [PATCH v2 1/9] arm64: kernel: get rid of x25 and x26 with 'global' scope Ard Biesheuvel
2016-08-24 14:35 ` [PATCH v2 2/9] arm64: kernel: fix style issues in sleep.S Ard Biesheuvel
2016-08-24 16:13 ` Mark Rutland
2016-08-24 14:36 ` [PATCH v2 3/9] arm64: kernel: use ordinary return/argument register for el2_setup() Ard Biesheuvel
2016-08-24 16:20 ` Mark Rutland
2016-08-24 14:36 ` Ard Biesheuvel [this message]
2016-08-24 20:36 ` [PATCH v2 4/9] arm64: head.S: move KASLR processing out of __enable_mmu() Mark Rutland
2016-08-24 20:44 ` Ard Biesheuvel
2016-08-24 20:46 ` Mark Rutland
2016-08-25 13:59 ` Ard Biesheuvel
2016-08-30 10:24 ` Mark Rutland
2016-08-30 13:45 ` Mark Rutland
2016-08-24 14:36 ` [PATCH v2 5/9] arm64: kernel: use x30 for __enable_mmu return address Ard Biesheuvel
2016-08-24 14:36 ` [PATCH v2 6/9] arm64: call __enable_mmu as an ordinary function for secondary/resume Ard Biesheuvel
2016-08-30 14:07 ` Mark Rutland
2016-08-24 14:36 ` [PATCH v2 7/9] arm64: kernel: drop use of x24 from primary boot path Ard Biesheuvel
2016-08-30 14:26 ` Mark Rutland
2016-08-24 14:36 ` [PATCH v2 8/9] arm64: head.S: use ordinary stack frame for __primary_switched() Ard Biesheuvel
2016-08-30 14:38 ` Mark Rutland
2016-08-24 14:36 ` [PATCH v2 9/9] arm64: head.S: document the use of callee saved registers Ard Biesheuvel
2016-08-30 14:43 ` Mark Rutland
2016-08-30 14:48 ` [PATCH v2 0/9] arm64: clean up early boot function calls Mark Rutland
2016-08-30 14:50 ` Ard Biesheuvel
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