On 20.05.16 08:53, Huan Wang wrote:
On 05/19/2016 10:26 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 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/cpu/armv8/transition.S | 8 ++--- arch/arm/include/asm/macro.h | 80
+++++++++++++++++++++++++++++++++++++----
arch/arm/include/asm/system.h | 25 +++++++++++-- arch/arm/lib/bootm.c | 26 +++++++++++--- common/image-fit.c | 12 ++++++- 5 files changed, 133 insertions(+), 18 deletions(-)
diff --git a/arch/arm/cpu/armv8/transition.S b/arch/arm/cpu/armv8/transition.S index 253a39b..9fa3b59 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, x1, x2, x3, x4, x5, x6 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, x1, x2, x3, x4, x5, x6 ENDPROC(armv8_switch_to_el1) diff --git a/arch/arm/include/asm/macro.h b/arch/arm/include/asm/macro.h index 9bb0efa..56d77f6 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__
/*
@@ -135,9 +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
+.macro armv8_switch_to_el2_m, xreg1, xreg2, xreg3, xreg4, xreg5, +xreg6, xreg7
These arguments should probably get documented :). Also xreg4 doesn't seem to actually be a scratch register, but a real parameter. So please name it accordingly.
[Alison Wang] Ok, I will add the descriptions for these arguments. Not only xreg4, xreg1, xreg2 and xreg3 are real parameters too. I will rename them in the next version.
- mov \xreg5, \xreg1
- mov \xreg6, \xreg2
- mov \xreg7, \xreg3
- /*
* If the next lower exception level is AArch64, 64bit EL2 | HCE |SMD |
* RES1 (Bits[5:4]) | Non-secure EL0/EL1. If the next lowerexception
* level is AArch32, 32bit EL2 | HCE | SMD | RES1 (Bits[5:4]) |* Non-secure EL0/EL1.*/- mov \xreg1, #0x1b1
- lsl \xreg2, \xreg4, #10
- orr \xreg1, \xreg1, \xreg2
Is there any way you can make this obvious from the code? Basically we would want something like
mov \xreg1, #(SCR_EL3_EL2_AA64 | SCR_EL3_HCE | SCR_EL3_SMD ...)
I'm sure there are creative ways to achieve this even with the high bits set. Maybe ldr = works?
[Alison Wang] Yes, I will change them and make them obvious.
msr scr_el3, \xreg1 msr cptr_el3, xzr /* Disable coprocessor traps to EL3
*/
mov \xreg1, #0x33ff @@ -156,18 +170,46 @@ lr .req x30 movk \xreg1, #0x30C5, lsl #16 msr sctlr_el2, \xreg1
- /* 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 */
- /* Check switch to AArch64 EL2 or AArch32 Hypervisor mode */
- ldr \xreg1, =ES_TO_AARCH64
- cmp \xreg4, \xreg1
- b.eq 1f
- b.ne 2f
Just b.ne should be enough, no?
[Alison Wang] Yes, you are right.
+1:
- /* Return to the EL2_SP2 mode from EL3 */ mov \xreg1, #0x3c9
Magic values again :). Please convert them to constants getting ORed.
[Alison Wang] Ok, I will change the original magic values too.
msr spsr_el3, \xreg1 /* EL2_SP2 | D | A | I | F */ msr elr_el3, lr
- mov \xreg1, \xreg5
- mov \xreg2, \xreg6
- mov \xreg3, \xreg7
- eret
+2:
- /* Return to AArch32 Hypervisor mode */
- mov \xreg1, #0x1da
- msr spsr_el3, \xreg1 /* Hyp | D | A | I | F */
- msr elr_el3, \xreg5
- mov \xreg1, #0
- mov \xreg2, \xreg6
- mov \xreg3, \xreg7 eret
- .endm
-.macro armv8_switch_to_el1_m, xreg1, xreg2 +.macro armv8_switch_to_el1_m, xreg1, xreg2, xreg3, xreg4, xreg5,
xreg6, xreg7
- mov \xreg5, \xreg1
- mov \xreg6, \xreg2
- mov \xreg7, \xreg3
- /* Initialize Generic Timers */ mrs \xreg1, cnthctl_el2 orr \xreg1, \xreg1, #0x3 /* Enable EL1 access to timers */
@@ -188,7 +230,7 @@ lr .req x30 msr cpacr_el1, \xreg1 /* Enable FP/SIMD at EL1 */
/* Initialize HCR_EL2 */
- mov \xreg1, #(1 << 31) /* 64bit EL1 */
- lsl \xreg1, \xreg4, #31
This deserves a comment. Imagine you read this code again in 5 years. Would you still understand what's going on?
[Alison Wang] Ok, I will add a comment.
orr \xreg1, \xreg1, #(1 << 29) /* Disable HVC */ msr hcr_el2, \xreg1
@@ -203,15 +245,39 @@ lr .req x30 movk \xreg1, #0x30d0, lsl #16 msr sctlr_el1, \xreg1
- /* Return to the EL1_SP1 mode from EL2 */ mov \xreg1, sp msr sp_el1, \xreg1 /* Migrate SP */ mrs \xreg1, vbar_el2 msr vbar_el1, \xreg1 /* Migrate VBAR */
- /* Check switch to AArch64 EL1 or AArch32 Supervisor mode */
- ldr \xreg1, =ES_TO_AARCH64
- cmp \xreg4, \xreg1
- b.eq 1f
- b.ne 2f
+1:
- /* Return to the EL1_SP1 mode from EL2 */ mov \xreg1, #0x3c5 msr spsr_el2, \xreg1 /* EL1_SP1 | D | A | I | F */ msr elr_el2, lr
- mov \xreg1, \xreg5
- mov \xreg2, \xreg6
- mov \xreg3, \xreg7
- eret
+2:
/* Return to the Supervisor mode from EL2 */
mov \xreg1, #0x1d3
msr spsr_el2, \xreg1 /* Supervisor | D | A | I | F */
msr elr_el2, \xreg5
mov \xreg1, #0
mov \xreg2, \xreg6
mov \xreg3, \xreg7 eret
.endm
#if defined(CONFIG_GICV3)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 9ae890a..fcfe3ae 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -17,6 +17,9 @@ #define CR_WXN (1 << 19) /* Write Permision Imply XN */ #define CR_EE (1 << 25) /* Exception (Big) Endian */
+#define ES_TO_AARCH64 1 +#define ES_TO_AARCH32 0
#ifndef __ASSEMBLY__
u64 get_page_table_size(void);
@@ -100,8 +103,26 @@ void __asm_invalidate_icache_all(void); int __asm_flush_l3_cache(void); void __asm_switch_ttbr(u64 new_ttbr);
-void armv8_switch_to_el2(void); -void armv8_switch_to_el1(void); +/*
- Switch from EL3 to EL2 for ARMv8
- @entry_point: kernel entry point
- @mach_nr: machine nr
- @fdt_addr: fdt address
- @es_flag: execution state flag, ES_TO_AARCH64 or ES_TO_AARCH32
- */
+void armv8_switch_to_el2(u64 entry_point, u64 mach_nr, u64 fdt_addr,
u64 es_flag);+/*
- Switch from EL2 to EL1 for ARMv8
- @entry_point: kernel entry point
- @mach_nr: machine nr
- @fdt_addr: fdt address
- @es_flag: execution state flag, ES_TO_AARCH64 or ES_TO_AARCH32
- */
+void armv8_switch_to_el1(u64 entry_point, u64 mach_nr, u64 fdt_addr,
u64 es_flag);diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c index 0838d89..f6f685a 100644 --- a/arch/arm/lib/bootm.c +++ b/arch/arm/lib/bootm.c @@ -193,9 +193,9 @@ static void do_nonsec_virt_switch(void) { smp_kick_all_cpus(); dcache_disable(); /* flush cache before swtiching to EL2 */
- armv8_switch_to_el2();
- armv8_switch_to_el2(0, 0, 0, ES_TO_AARCH64);
Just rename the existing function to armv8_switch_to_el2_adv() or so and provide armv8_switch_to_el2() as static inline function that simply invokes armv8_switch_to_el2_adv(0, 0, 0, ES_TO_AARCH64);
[Alison Wang] I didn't know why you suggest to do so. Please explain it. Thanks.
I guess with my suggestion below this wouldn't make much sense anymore, so it's fine the way it is.
#ifdef CONFIG_ARMV8_SWITCH_TO_EL1
- armv8_switch_to_el1();
- armv8_switch_to_el1(0, 0, 0, ES_TO_AARCH64); #endif } #endif
@@ -286,8 +286,26 @@ static void boot_jump_linux(bootm_headers_t
*images, int flag)
announce_and_cleanup(fake);
if (!fake) {
do_nonsec_virt_switch();kernel_entry(images->ft_addr, NULL, NULL, NULL);
if ((IH_ARCH_DEFAULT == IH_ARCH_ARM64) &&(images->os.arch == IH_ARCH_ARM)) {smp_kick_all_cpus();dcache_disable();This open codes part of do_nonsec_virt_switch().
Could we just clean up all of that mess a bit more maybe? How about you call
do_nonsec_virt_switch(ES_EL2 | ES_AARCH32, entry, images->ft_addr) or do_nonsec_virt_switch(ES_EL1 | ES_AARCH64, entry, images->ft_addr)
Then the if() would only need to set ES_AARCH32/64 in a variable and everything else goes along the same code.
[Alison Wang] It sounds fine. I will try to do it in the next version.
+#ifdef CONFIG_ARMV8_SWITCH_TO_EL1
armv8_switch_to_el2(0, 0, 0, ES_TO_AARCH64);armv8_switch_to_el1((u64)images->ep,(u64)gd->bd->bi_arch_number,(u64)images->ft_addr,ES_TO_AARCH32);+#else
armv8_switch_to_el2((u64)images->ep,(u64)gd->bd->bi_arch_number,(u64)images->ft_addr,ES_TO_AARCH32);+#endif
} else {do_nonsec_virt_switch();kernel_entry(images->ft_addr, NULL, NULL, NULL);}a/common/image-fit.c b/common/image-fit.c index 25f8a11..2986469 100644 --- a/common/image-fit.c +++ b/common/image-fit.c @@ -1163,7 +1163,8 @@ int fit_image_check_arch(const void *fit, int
noffset, uint8_t arch)
if (fit_image_get_arch(fit, noffset, &image_arch)) return 0; return (arch == image_arch) ||
(arch == IH_ARCH_I386 && image_arch == IH_ARCH_X86_64);
(arch == IH_ARCH_I386 && image_arch == IH_ARCH_X86_64) ||(arch == IH_ARCH_ARM64 && image_arch == IH_ARCH_ARM);This should be a Kconfig option. ThunderX doesn't support AArch32 execution.
[Alison Wang] I can't understand your meaning. Can you clarify it?
U-Boot supports the ThunderX SoC which uses Cavium's own ARMv8 core implementation. That core does not support running AArch32 code.
Alex