[PATCH v5 09/21] arm64: head: pass ID map root table address to __enable_mmu()

Ard Biesheuvel
2022-06-24T15:11:05Z

We will be adding an initial ID map that covers the entire kernel image,
so we will pass the actual ID map root table to use to __enable_mmu(),
rather than hard code it.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/kernel/head.S | 14 ++++++++------
arch/arm64/kernel/sleep.S | 1 +
2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 1cbc52097bf9..70c462bbd6bf 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -595,6 +595,7 @@ SYM_FUNC_START_LOCAL(secondary_startup)
bl __cpu_secondary_check52bitva
bl __cpu_setup // initialise processor
adrp x1, swapper_pg_dir
+ adrp x2, idmap_pg_dir
bl __enable_mmu
ldr x8, =__secondary_switched
br x8
@@ -648,6 +649,7 @@ SYM_FUNC_END(__secondary_too_slow)
*
* x0 = SCTLR_EL1 value for turning on the MMU.
* x1 = TTBR1_EL1 value
+ * x2 = ID map root table address
*
* Returns to the caller via x30/lr. This requires the caller to be covered
* by the .idmap.text section.
@@ -656,14 +658,13 @@ SYM_FUNC_END(__secondary_too_slow)
* If it isn't, park the CPU
*/
SYM_FUNC_START(__enable_mmu)
- mrs x2, ID_AA64MMFR0_EL1
- ubfx x2, x2, #ID_AA64MMFR0_TGRAN_SHIFT, 4
- cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED_MIN
+ mrs x3, ID_AA64MMFR0_EL1
+ ubfx x3, x3, #ID_AA64MMFR0_TGRAN_SHIFT, 4
+ cmp x3, #ID_AA64MMFR0_TGRAN_SUPPORTED_MIN
b.lt __no_granule_support
- cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED_MAX
+ cmp x3, #ID_AA64MMFR0_TGRAN_SUPPORTED_MAX
b.gt __no_granule_support
- update_early_cpu_boot_status 0, x2, x3
- adrp x2, idmap_pg_dir
+ update_early_cpu_boot_status 0, x3, x4
phys_to_ttbr x1, x1
phys_to_ttbr x2, x2
msr ttbr0_el1, x2 // load TTBR0
@@ -819,6 +820,7 @@ SYM_FUNC_START_LOCAL(__primary_switch)
#endif

adrp x1, init_pg_dir
+ adrp x2, idmap_pg_dir
bl __enable_mmu
#ifdef CONFIG_RELOCATABLE
#ifdef CONFIG_RELR
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index 4ea9392f86e0..e36b09d942f7 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -104,6 +104,7 @@ SYM_CODE_START(cpu_resume)
bl __cpu_setup
/* enable the MMU early - so we can access sleep_save_stash by va */
adrp x1, swapper_pg_dir
+ adrp x2, idmap_pg_dir
bl __enable_mmu
ldr x8, =_cpu_resume
br x8