On 07/03/2016 08:39 PM, Huan Wang wrote: >> On 30.06.16 09:16, Huan Wang wrote: >>> Hi, Alex, >>> >>>>> Am 15.06.2016 um 05:04 schrieb Huan Wang <alison.w...@nxp.com>: >>>>> >>>>> Hi, Alex, >>>>> >>>>>>> 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....@nxp.com> >>>>>>> Signed-off-by: Alison Wang <alison.w...@nxp.com> >>>>>>> Signed-off-by: Chenhui Zhao <chenhui.z...@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); >>>>> [Alison Wang] I don't agree it would make a lot of sense if we could >>>>> *always* jump to ep. >>>>> If we switch to EL2 AArch32 mode, it will happen at the last minute >>>>> from U-Boot to kernel. The ep is the entry pointer for kernel. >>>>> If we switch to EL2 AArch64 mode, it will happen earlier. For >>>>> primary core, it will call kernel entry after the switch. For >>>>> secondary cores, it will switch from EL3 AArch64 to EL2 AArch64 >>>>> first, then it will wait until the spin-table is written by the >>>>> kernel, later it will jump >>>> to kernel. >>>> >>>> Then jump to a separate function that continues the execution stream. >>>> I really think we should keep the interface between both flags as >>>> identical as possible. >>> [Alison Wang] I think you are right. I will change the code to >>> *always* jump to ep in v5. >>>> >>>>>> >>>>>> 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. >>>>> [Alison Wang] I agreed with you to remove the EL1 mess. >>>> >>>> Awesome, thanks. >>> [Alison Wang] When I tried to remove the EL1 mess, I found >>> CONFIG_ARMV8_SWITCH_TO_EL1 is enabled for Versatile Express Aemv8a. If >>> that platform uses it, I have a concern about removing it. >> >> Do you have access to the respective simulator? It's probably only >> enabled because in the very very very early days of Linux bringup Linux >> didn't know how to run in EL2 yet. So we can probably just drop it. >> >> But let's CC people who might know :). >> > [Alison Wang] Alex, thanks for the explanation. > > Does anyone disagree to remove CONFIG_ARMV8_SWITCH_TO_EL1 and other > corresponding functions? > If there is no disagreement, I will remove them in the v5 patches. >
If nobody uses EL1, go ahead to drop it. It may be a good idea to check this macro and throw an error if found. York _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
