From: James Morse <james.morse@xxxxxxx>
el2_setup() doesn't just configure el2, it configures el1 too. This
means we can't use it to re-configure el2 after resume from hibernate,
as we will be returned to el1 with the MMU turned off.
Split the sctlr_el1 setting code up, so that el2_setup() accepts an
initial value as an argument. This value will be ignored if el2_setup()
is called at el1: the running value will be preserved with endian
correction.
Hibernate can now call el2_setup() to re-configure el2, passing the
current sctlr_el1 as an argument.
Signed-off-by: James Morse <james.morse at arm.com>
---
arch/arm64/include/asm/assembler.h | 10 ++++++++++
arch/arm64/kernel/head.S | 19 ++++++++++++-------
arch/arm64/kernel/sleep.S | 1 +
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index a04fd7a..627d66e 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -311,6 +311,16 @@ lr .req x30 // link register
.endm
/*
+ * Generate the initial sctlr_el1 value for el2_setup to set if we boot at EL2.
+ */
+ .macro init_sctlr_el1 reg
+ mov \reg, #0x0800 // Set/clear RES{1,0} bits
+CPU_BE( movk \reg, #0x33d0, lsl #16) // Set EE and E0E on BE systems
+CPU_LE( movk \reg, #0x30d0, lsl #16) // Clear EE and E0E on LE systems
+ .endm
+
+/*
+
* Annotate a function as position independent, i.e., safe to be called before
* the kernel virtual mapping is activated.
*/
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 6e8e803..e8a15163 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -208,6 +208,7 @@ section_table:
ENTRY(stext)
bl preserve_boot_args
+ init_sctlr_el1 x0
bl el2_setup // Drop to EL1, w20=cpu_boot_mode
mov x23, xzr // KASLR offset, defaults to 0
adrp x24, __PHYS_OFFSET
@@ -514,8 +515,12 @@ ENTRY(kimage_vaddr)
*
* Returns either BOOT_CPU_MODE_EL1 or BOOT_CPU_MODE_EL2 in x20 if
* booted in EL1 or EL2 respectively.
+ *
+ * If booted in EL2, SCTLR_EL1 will be initialised with the value in x0
+ * (otherwise the existing value will be preserved, with endian correction).
*/
ENTRY(el2_setup)
+ mov x1, x0 // preserve passed-in sctlr_el1
mrs x0, CurrentEL
cmp x0, #CurrentEL_EL2
b.ne 1f
@@ -524,7 +529,7 @@ CPU_BE( orr x0, x0, #(1 << 25) ) // Set the EE bit for EL2
CPU_LE( bic x0, x0, #(1 << 25) ) // Clear the EE bit for EL2
msr sctlr_el2, x0
b 2f
-1: mrs x0, sctlr_el1
+1: mrs x0, sctlr_el1 // ignore passed-in sctlr_el1
CPU_BE( orr x0, x0, #(3 << 24) ) // Set the EE and E0E bits for EL1
CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1
msr sctlr_el1, x0
@@ -578,6 +583,10 @@ set_hcr:
3:
#endif
+ /* use sctlr_el1 value we were provided with */
+CPU_BE( orr x1, x1, #(3 << 24) ) // Set the EE and E0E bits for EL1
+CPU_LE( bic x1, x1, #(3 << 24) ) // Clear the EE and E0E bits for EL1
+ msr sctlr_el1, x1
/* Populate ID registers. */
mrs x0, midr_el1
@@ -585,12 +594,6 @@ set_hcr:
msr vpidr_el2, x0
msr vmpidr_el2, x1
- /* sctlr_el1 */
- mov x0, #0x0800 // Set/clear RES{1,0} bits
-CPU_BE( movk x0, #0x33d0, lsl #16 ) // Set EE and E0E on BE systems
-CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems
- msr sctlr_el1, x0
-
/* Coprocessor traps. */
mov x0, #0x33ff
msr cptr_el2, x0 // Disable copro. traps to EL2
@@ -667,6 +670,7 @@ ENTRY(__boot_cpu_mode)
* cores are held until we're ready for them to initialise.
*/
ENTRY(secondary_holding_pen)
+ init_sctlr_el1 x0
bl el2_setup // Drop to EL1, w20=cpu_boot_mode
bl set_cpu_boot_mode_flag
mrs x0, mpidr_el1
@@ -685,6 +689,7 @@ ENDPROC(secondary_holding_pen)
* be used where CPUs are brought online dynamically by the kernel.
*/
ENTRY(secondary_entry)
+ init_sctlr_el1 x0
bl el2_setup // Drop to EL1
bl set_cpu_boot_mode_flag
b secondary_startup
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index fd10eb6..f60ddc7 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -160,6 +160,7 @@ cpu_resume_after_mmu:
ENDPROC(cpu_resume_after_mmu)
ENTRY(cpu_resume)
+ init_sctlr_el1 x0
bl el2_setup // if in EL2 drop to EL1 cleanly
mrs x1, mpidr_el1
adrp x8, mpidr_hash
--
2.5.0
