On 06/08/2016 07:14 AM, Alison Wang wrote:
To support loading a 32-bit OS, the execution state will change from AArch64 to AArch32 when jumping to kernel.
The architecture information will be got through checking FIT image, then U-Boot will load 32-bit OS or 64-bit OS automatically.
Signed-off-by: Ebony Zhu ebony.zhu@nxp.com Signed-off-by: Alison Wang alison.wang@nxp.com Signed-off-by: Chenhui Zhao chenhui.zhao@nxp.com
Changes in v4:
- Correct config ARM64_SUPPORT_AARCH32.
- Omit arch and ftaddr arguments.
- Rename "xreg5" to "tmp".
- Use xxx_RES1 to combine all RES1 fields in xxx register.
- Use an immediate cmp directly.
- Use #ifdef for CONFIG_ARM64_SUPPORT_AARCH32.
Changes in v3:
- Comments the functions and the arguments.
- Rename the real parameters.
- Use the macros instead of the magic values.
- Remove the redundant codes.
- Clean up all of the mess in boot_jump_linux().
- Add CONFIG_ARM64_SUPPORT_AARCH32 to detect for some ARM64 system doesn't support AArch32 state.
Changes in v2:
armv8_switch_to_el2_aarch32() is removed. armv8_switch_to_el2_m is used to switch to AArch64 EL2 or AArch32 Hyp.
armv8_switch_to_el1_aarch32() is removed. armv8_switch_to_el1_m is used to switch to AArch64 EL1 or AArch32 SVC.
arch/arm/Kconfig | 6 ++ arch/arm/cpu/armv8/start.S | 1 + arch/arm/cpu/armv8/transition.S | 8 +- arch/arm/include/asm/macro.h | 172 ++++++++++++++++++++++++++++++---------- arch/arm/include/asm/system.h | 111 +++++++++++++++++++++++++- arch/arm/lib/bootm.c | 19 ++++- common/image-fit.c | 19 ++++- 7 files changed, 284 insertions(+), 52 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 77eab66..9cf4acd 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -91,6 +91,12 @@ config SYS_L2CACHE_OFF If SoC does not support L2CACHE or one do not want to enable L2CACHE, choose this option.
+config ARM64_SUPPORT_AARCH32
- bool "ARM64 system support AArch32 execution state"
- default y if ARM64 && !TARGET_THUNDERX_88XX
- help
This ARM64 system supports AArch32 execution state.- choice prompt "Target select" default TARGET_HIKEY
diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index e933021..dd69501 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -234,6 +234,7 @@ WEAK(lowlevel_init) /* * All slaves will enter EL2 and optionally EL1. */
- ldr x3, =ES_TO_AARCH64 bl armv8_switch_to_el2 #ifdef CONFIG_ARMV8_SWITCH_TO_EL1 bl armv8_switch_to_el1
diff --git a/arch/arm/cpu/armv8/transition.S b/arch/arm/cpu/armv8/transition.S index 253a39b..e61b6ae 100644 --- a/arch/arm/cpu/armv8/transition.S +++ b/arch/arm/cpu/armv8/transition.S @@ -11,13 +11,13 @@ #include <asm/macro.h>
ENTRY(armv8_switch_to_el2)
- switch_el x0, 1f, 0f, 0f
- switch_el x4, 1f, 0f, 0f 0: ret
-1: armv8_switch_to_el2_m x0 +1: armv8_switch_to_el2_m x0, x3, x4 ENDPROC(armv8_switch_to_el2)
ENTRY(armv8_switch_to_el1)
- switch_el x0, 0f, 1f, 0f
- switch_el x4, 0f, 1f, 0f 0: ret
-1: armv8_switch_to_el1_m x0, x1 +1: armv8_switch_to_el1_m x0, x3, x4 ENDPROC(armv8_switch_to_el1) diff --git a/arch/arm/include/asm/macro.h b/arch/arm/include/asm/macro.h index 9bb0efa..109724f 100644 --- a/arch/arm/include/asm/macro.h +++ b/arch/arm/include/asm/macro.h @@ -8,6 +8,9 @@
#ifndef __ASM_ARM_MACRO_H__ #define __ASM_ARM_MACRO_H__
+#include <asm/system.h>
#ifdef __ASSEMBLY__
/*
@@ -135,13 +138,20 @@ lr .req x30 #endif .endm
-.macro armv8_switch_to_el2_m, xreg1
- /* 64bit EL2 | HCE | SMD | RES1 (Bits[5:4]) | Non-secure EL0/EL1 */
- mov \xreg1, #0x5b1
- msr scr_el3, \xreg1
+/*
- Switch from EL3 to EL2 for ARMv8
- @ep: kernel entry point
- @flag: The execution state flag for lower exception
level, ES_TO_AARCH64 or ES_TO_AARCH32
- @tmp: temporary register
- x1 is machine nr and x2 is ftaddr, they will be passed
- to the guest.
- */
+.macro armv8_switch_to_el2_m, ep, flag, tmp msr cptr_el3, xzr /* Disable coprocessor traps to EL3 */
- mov \xreg1, #0x33ff
- msr cptr_el2, \xreg1 /* Disable coprocessor traps to EL2 */
mov \tmp, #CPTR_EL2_RES1
msr cptr_el2, \tmp /* Disable coprocessor traps to EL2 */
/* Initialize Generic Timers */ msr cntvoff_el2, xzr
@@ -152,45 +162,91 @@ lr .req x30 * and RES0 bits (31,30,27,26,24,21,20,17,15-13,10-6) + * EE,WXN,I,SA,C,A,M to 0 */
- mov \xreg1, #0x0830
- movk \xreg1, #0x30C5, lsl #16
- msr sctlr_el2, \xreg1
ldr \tmp, =(SCTLR_EL2_RES1 | SCTLR_EL2_EE_LE |\
SCTLR_EL2_WXN_DIS | SCTLR_EL2_ICACHE_DIS |\SCTLR_EL2_SA_DIS | SCTLR_EL2_DCACHE_DIS |\SCTLR_EL2_ALIGN_DIS | SCTLR_EL2_MMU_DIS)msr sctlr_el2, \tmp
mov \tmp, sp
msr sp_el2, \tmp /* Migrate SP */
mrs \tmp, vbar_el3
msr vbar_el2, \tmp /* Migrate VBAR */
/* Check switch to AArch64 EL2 or AArch32 Hypervisor mode */
cmp \flag, #ES_TO_AARCH32
b.eq 1f
/*
* The next lower exception level is AArch64, 64bit EL2 | HCE |* SMD | RES1 (Bits[5:4]) | Non-secure EL0/EL1.*/ldr \tmp, =(SCR_EL3_RW_AARCH64 | SCR_EL3_HCE_EN |\
SCR_EL3_SMD_DIS | SCR_EL3_RES1 |\SCR_EL3_NS_EN)msr scr_el3, \tmp
/* Return to the EL2_SP2 mode from EL3 */
- mov \xreg1, sp
- msr sp_el2, \xreg1 /* Migrate SP */
- mrs \xreg1, vbar_el3
- msr vbar_el2, \xreg1 /* Migrate VBAR */
- mov \xreg1, #0x3c9
- msr spsr_el3, \xreg1 /* EL2_SP2 | D | A | I | F */
- ldr \tmp, =(SPSR_EL_DEBUG_MASK | SPSR_EL_SERR_MASK |\
SPSR_EL_IRQ_MASK | SPSR_EL_FIQ_MASK |\SPSR_EL_M_AARCH64 | SPSR_EL_M_EL2H)- msr spsr_el3, \tmp msr elr_el3, lr
So if we switch into AArch64 mode, we return ...
eret
+1:
- /*
* The next lower exception level is AArch32, 32bit EL2 | HCE |* SMD | RES1 (Bits[5:4]) | Non-secure EL0/EL1.*/- ldr \tmp, =(SCR_EL3_RW_AARCH32 | SCR_EL3_HCE_EN |\
SCR_EL3_SMD_DIS | SCR_EL3_RES1 |\SCR_EL3_NS_EN)- msr scr_el3, \tmp
- /* Return to AArch32 Hypervisor mode */
- ldr \tmp, =(SPSR_EL_END_LE | SPSR_EL_ASYN_MASK |\
SPSR_EL_IRQ_MASK | SPSR_EL_FIQ_MASK |\SPSR_EL_T_A32 | SPSR_EL_M_AARCH32 |\SPSR_EL_M_HYP)- msr spsr_el3, \tmp
- msr elr_el3, \ep
- mov \ep, #0
... while if we switch to AArch32 mode we jump to ep.
I think it would make a lot of sense if we could *always* jump to ep. Just swizzle the argument order so that you get
if ((IH_ARCH_DEFAULT == IH_ARCH_ARM64) && (images->os.arch == IH_ARCH_ARM)) armv8_switch_to_el2(0, gd->bd->bi_arch_number, (uintptr_t)images->ft_addr, (u64)images->ep, ES_TO_AARCH32); else armv8_switch_to_el2((uintptr_t)images->ft_addr, 0 0, images->ep, ES_TO_AARCH64);
If you *really really really* are attached to booting into EL1, just add a small function that calls armv8_switch_to_el1() for you and pass the pointer to that as ep to the el2 switch. If I were you I'd just remove the EL1 mess.
Alex