[U-Boot] [PATCH v3 1/2] armv8: Support loading 32-bit OS in AArch32 execution state

Huan Wang alison.wang at nxp.com
Fri Jun 3 11:31:45 CEST 2016


> On 03.06.16 05:11, Huan Wang wrote:
> >> On 26.05.16 10:41, 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 at nxp.com>
> >>> Signed-off-by: Alison Wang <alison.wang at nxp.com>
> >>> Signed-off-by: Chenhui Zhao <chenhui.zhao at nxp.com>
> >>> ---
> >>> 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/transition.S |   8 +-
> >>>  arch/arm/include/asm/macro.h    | 174
> ++++++++++++++++++++++++++++++-
> >> ---------
> >>>  arch/arm/include/asm/system.h   | 118 ++++++++++++++++++++++++++-
> >>>  arch/arm/lib/bootm.c            |  19 ++++-
> >>>  common/image-fit.c              |  14 +++-
> >>>  6 files changed, 287 insertions(+), 52 deletions(-)
> >>>
> >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index
> >>> 729b181..794cb4f 100644
> >>> --- a/arch/arm/Kconfig
> >>> +++ b/arch/arm/Kconfig
> >>> @@ -77,6 +77,12 @@ 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 && !CONFIG_THUNDERX
> >>
> >> I don't think that works. In Kconfig you need to omit the CONFIG_
> parts.
> >> It's "ARM64" also, not "CONFIG_ARM64".
> >>
> >> Please just try to run a local make defconfig on the thunderx
> >> reference system and see whether it includes the option or not.
> > [Alison Wang] Yes, I missed it. Will change in the next version.
> >>
> >>> +	help
> >>> +	  This ARM64 system supports AArch32 execution state.
> >>> +
> >>>  choice
> >>>  	prompt "Target select"
> >>>  	default TARGET_HIKEY
> >>> diff --git a/arch/arm/cpu/armv8/transition.S
> >>> b/arch/arm/cpu/armv8/transition.S index 253a39b..417e8b4 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
> >>>  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
> >>>  ENDPROC(armv8_switch_to_el1)
> >>> diff --git a/arch/arm/include/asm/macro.h
> >>> b/arch/arm/include/asm/macro.h index 9bb0efa..dd2c510 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 +138,18 @@ 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
> >>> + * @arch:   machine nr
> >>> + * @ftaddr: fdt address
> >>> + * @flag:   The execution state flag for lower exception
> >>> + *          level, ES_TO_AARCH64 or ES_TO_AARCH32
> >>> + */
> >>> +.macro armv8_switch_to_el2_m, ep, arch, ftaddr, flag, xreg5
> >>
> >> You're never really using the arch and ftaddr arguments. Just
> >> describe in the macro header that they need to be in x1 and x2
> >> respectively and leave them out of the argument list for the macro.
> > [Alison Wang] Do you mean rename arch and ftaddr to x1 and x2 here?
> 
> I mean omit arch and ftaddr from the macro arguments and instead mention
> that x1 and x2 get passed as x1 and x2 to the guest and are usually
> "ftaddr" and "arch".
> 
> Also it would make the code more consistent to always use ep.
[Alison Wang] I don't think arch and ftaddr can be removed from the
macro arguments in the current code. For 32-bit kernel startup entry
point, the requirements are: r0 = 0, r1 = machine nr, r2 = atags or
dtb pointer.
> 
> 
> +/*
> + * Switch from EL3 to EL2 for ARMv8 and jump to @ep.
> + *
> + * @flag:   The execution state flag for lower exception
> + *          level, ES_TO_AARCH64 or ES_TO_AARCH32
> + *
> + * When flag == ES_TO_AARCH32:
> + * @ep:     location to jump to in AArch32 EL2 mode
> + * x1:      "Machine ID" for Linux payloads
> + * x2:      "DT Address" for Linux payloads
> + *
> + * When flag == ES_TO_AARCH64:
> + * @ep:     location to jump to in AArch64 EL2 mode
> + * x1:      "DT Address" for Linux payloads
> + */
> +.macro armv8_switch_to_el2_m, ep, flag, tmpreg
> 
> 
> >>
> >> Also please rename "xreg5" to something like "scratchreg" or "tmp" or
> >> "tmpreg". Then it's more obvious what this argument is about.
> > [Alison Wang] Ok.
> >>
> >>>  	msr	cptr_el3, xzr		/* Disable coprocessor traps to EL3
> >> */
> >>> -	mov	\xreg1, #0x33ff
> >>> -	msr	cptr_el2, \xreg1	/* Disable coprocessor traps to EL2 */
> >>> +	mov	\xreg5, #(CPTR_EL2_BIT13_12_RES1 | CPTR_EL2_BIT9_0_RES1)
> >>> +	msr	cptr_el2, \xreg5	/* Disable coprocessor traps to EL2 */
> >>>
> >>>  	/* Initialize Generic Timers */
> >>>  	msr	cntvoff_el2, xzr
> >>> @@ -152,45 +160,92 @@ 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	\xreg5, =(SCTLR_EL2_BIT29_28_RES1 | SCTLR_EL2_EE_LE |\
> >>> +			  SCTLR_EL2_BIT23_22_RES1 | SCTLR_EL2_WXN_DIS |\
> >>> +			  SCTLR_EL2_BIT18_RES1 | SCTLR_EL2_BIT16_RES1 |\
> >>> +			  SCTLR_EL2_BIT11_RES1 | SCTLR_EL2_BIT5_4_RES1 |\
> >>> +			  SCTLR_EL2_SA_DIS | SCTLR_EL2_DCACHE_DIS |\
> >>> +			  SCTLR_EL2_ALIGN_DIS | SCTLR_EL2_MMU_DIS)
> >>
> >> Do you think you could just define something like SCTLR_EL2_RES1 in
> >> the header file that combines all RES1 fields already?
> > [Alison Wang] Ok, I think so.
> >>
> >>> +	msr	sctlr_el2, \xreg5
> >>> +
> >>> +	mov	\xreg5, sp
> >>> +	msr	sp_el2, \xreg5		/* Migrate SP */
> >>> +	mrs	\xreg5, vbar_el3
> >>> +	msr	vbar_el2, \xreg5	/* Migrate VBAR */
> >>> +
> >>> +	/* Check switch to AArch64 EL2 or AArch32 Hypervisor mode */
> >>> +	ldr	\xreg5, =ES_TO_AARCH32
> >>> +	cmp	\flag, \xreg5
> >>
> >> This can be an immediate cmp, no?
> >>
> >>   cmp \flag, #ES_TO_AARCH32
> > [Alison Wang] Yes, it can. Will change in the next version.
> >>
> >>> +	b.eq	1f
> >>> +
> >>> +	/*
> >>> +	 * The next lower exception level is AArch64, 64bit EL2 | HCE |
> >>> +	 * SMD | RES1 (Bits[5:4]) | Non-secure EL0/EL1.
> >>> +	 */
> >>> +	ldr	\xreg5, =(SCR_EL3_RW_AARCH64 | SCR_EL3_HCE_EN |\
> >>> +			  SCR_EL3_SMD_DIS | SCR_EL3_BIT5_4_RES1 |\
> >>> +			  SCR_EL3_NS_EN)
> >>
> >> Same here - just define a single mask for SCR_EL3_RES1.
> > [Alison Wang] Ok.
> >>
> >>> +	msr	scr_el3, \xreg5
> >>>
> >>>  	/* 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	\xreg5, =(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, \xreg5
> >>>  	msr	elr_el3, lr
> >>>  	eret
> >>> +
> >>> +1:
> >>> +	/*
> >>> +	 * The next lower exception level is AArch32, 32bit EL2 | HCE |
> >>> +	 * SMD | RES1 (Bits[5:4]) | Non-secure EL0/EL1.
> >>> +	 */
> >>> +	ldr	\xreg5, =(SCR_EL3_RW_AARCH32 | SCR_EL3_HCE_EN |\
> >>> +			  SCR_EL3_SMD_DIS | SCR_EL3_BIT5_4_RES1 |\
> >>> +			  SCR_EL3_NS_EN)
> >>> +	msr	scr_el3, \xreg5
> >>> +
> >>> +	/* Return to AArch32 Hypervisor mode */
> >>> +	ldr     \xreg5, =(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, \xreg5
> >>> +	msr     elr_el3, \ep
> >>> +
> >>> +	mov	\ep, #0
> >>> +	eret
> >>>  .endm
> >>>
> >>> -.macro armv8_switch_to_el1_m, xreg1, xreg2
> >>> +/*
> >>> + * Switch from EL2 to EL1 for ARMv8
> >>> + * @ep:     kernel entry point
> >>> + * @arch:   machine nr
> >>> + * @ftaddr: fdt address
> >>> + * @flag:   The execution state flag for lower exception
> >>> + *          level, ES_TO_AARCH64 or ES_TO_AARCH32
> >>> + */
> >>> +.macro armv8_switch_to_el1_m, ep, arch, ftaddr, flag, xreg5
> >>
> >> All the comments to the function above apply here too :).
> > [Alison Wang] Ok.
> >>
> >>>  	/* Initialize Generic Timers */
> >>> -	mrs	\xreg1, cnthctl_el2
> >>> -	orr	\xreg1, \xreg1, #0x3	/* Enable EL1 access to timers */
> >>> -	msr	cnthctl_el2, \xreg1
> >>> +	mrs	\xreg5, cnthctl_el2
> >>> +	/* Enable EL1 access to timers */
> >>> +	orr	\xreg5, \xreg5, #(CNTHCTL_EL2_EL1PCEN_EN |\
> >>> +		CNTHCTL_EL2_EL1PCTEN_EN)
> >>> +	msr	cnthctl_el2, \xreg5
> >>>  	msr	cntvoff_el2, xzr
> >>>
> >>>  	/* Initilize MPID/MPIDR registers */
> >>> -	mrs	\xreg1, midr_el1
> >>> -	mrs	\xreg2, mpidr_el1
> >>> -	msr	vpidr_el2, \xreg1
> >>> -	msr	vmpidr_el2, \xreg2
> >>> +	mrs	\xreg5, midr_el1
> >>> +	msr	vpidr_el2, \xreg5
> >>> +	mrs	\xreg5, mpidr_el1
> >>> +	msr	vmpidr_el2, \xreg5
> >>>
> >>>  	/* Disable coprocessor traps */
> >>> -	mov	\xreg1, #0x33ff
> >>> -	msr	cptr_el2, \xreg1	/* Disable coprocessor traps to EL2 */
> >>> +	mov	\xreg5, #(CPTR_EL2_BIT13_12_RES1 | CPTR_EL2_BIT9_0_RES1)
> >>> +	msr	cptr_el2, \xreg5	/* Disable coprocessor traps to EL2 */
> >>>  	msr	hstr_el2, xzr		/* Disable coprocessor traps to EL2
> >> */
> >>> -	mov	\xreg1, #3 << 20
> >>> -	msr	cpacr_el1, \xreg1	/* Enable FP/SIMD at EL1 */
> >>> -
> >>> -	/* Initialize HCR_EL2 */
> >>> -	mov	\xreg1, #(1 << 31)		/* 64bit EL1 */
> >>> -	orr	\xreg1, \xreg1, #(1 << 29)	/* Disable HVC */
> >>> -	msr	hcr_el2, \xreg1
> >>> +	mov	\xreg5, #(CPACR_EL1_FPEN_EN)
> >>> +	msr	cpacr_el1, \xreg5	/* Enable FP/SIMD at EL1 */
> >>>
> >>>  	/* SCTLR_EL1 initialization
> >>>  	 *
> >>> @@ -199,19 +254,56 @@ lr	.req	x30
> >>>  	 * UCI,EE,EOE,WXN,nTWE,nTWI,UCT,DZE,I,UMA,SED,ITD,
> >>>  	 * CP15BEN,SA0,SA,C,A,M to 0
> >>>  	 */
> >>> -	mov	\xreg1, #0x0800
> >>> -	movk	\xreg1, #0x30d0, lsl #16
> >>> -	msr	sctlr_el1, \xreg1
> >>> +	ldr	\xreg5, =(SCTLR_EL1_BIT29_28_RES1 | SCTLR_EL1_UCI_DIS |\
> >>> +			  SCTLR_EL1_EE_LE | SCTLR_EL1_BIT23_22_RES1 |\
> >>> +			  SCTLR_EL1_BIT20_RES1 | SCTLR_EL1_WXN_DIS |\
> >>> +			  SCTLR_EL1_NTWE_DIS | SCTLR_EL1_NTWI_DIS |\
> >>> +			  SCTLR_EL1_UCT_DIS | SCTLR_EL1_DZE_DIS |\
> >>> +			  SCTLR_EL1_ICACHE_DIS | SCTLR_EL1_BIT11_RES1 |\
> >>> +			  SCTLR_EL1_UMA_DIS | SCTLR_EL1_SED_EN |\
> >>> +			  SCTLR_EL1_ITD_EN | SCTLR_EL1_CP15BEN_DIS |\
> >>> +			  SCTLR_EL1_SA0_DIS | SCTLR_EL1_SA_DIS |\
> >>> +			  SCTLR_EL1_DCACHE_DIS | SCTLR_EL1_ALIGN_DIS |\
> >>> +			  SCTLR_EL1_MMU_DIS)
> >>
> >> Why are the caches getting disabled? Or did you just convert the old
> >> value to the define list?
> > [Alison Wang] Yes, I just convert the old value to the define list.
> >>
> >>> +	msr	sctlr_el1, \xreg5
> >>> +
> >>> +	mov	\xreg5, sp
> >>> +	msr	sp_el1, \xreg5		/* Migrate SP */
> >>> +	mrs	\xreg5, vbar_el2
> >>> +	msr	vbar_el1, \xreg5	/* Migrate VBAR */
> >>> +
> >>> +	/* Check switch to AArch64 EL1 or AArch32 Supervisor mode */
> >>> +	ldr	\xreg5, =ES_TO_AARCH32
> >>> +	cmp	\flag, \xreg5
> >>> +	b.eq	1f
> >>> +
> >>> +	/* Initialize HCR_EL2 */
> >>> +	ldr	\xreg5, =(HCR_EL2_RW_AARCH64 | HCR_EL2_HCD_DIS)
> >>> +	msr	hcr_el2, \xreg5
> >>>
> >>>  	/* 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 */
> >>> -	mov	\xreg1, #0x3c5
> >>> -	msr	spsr_el2, \xreg1	/* EL1_SP1 | D | A | I | F */
> >>> +	ldr	\xreg5, =(SPSR_EL_DEBUG_MASK | SPSR_EL_SERR_MASK |\
> >>> +			  SPSR_EL_IRQ_MASK | SPSR_EL_FIQ_MASK |\
> >>> +			  SPSR_EL_M_AARCH64 | SPSR_EL_M_EL1H)
> >>> +	msr	spsr_el2, \xreg5
> >>>  	msr	elr_el2, lr
> >>>  	eret
> >>> +
> >>> +1:
> >>> +	/* Initialize HCR_EL2 */
> >>> +	ldr	\xreg5, =(HCR_EL2_RW_AARCH32 | HCR_EL2_HCD_DIS)
> >>> +	msr	hcr_el2, \xreg5
> >>> +
> >>> +	/* Return to AArch32 Supervisor mode from EL2 */
> >>> +	ldr	\xreg5, =(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_SVC)
> >>> +	msr     spsr_el2, \xreg5
> >>> +	msr     elr_el2, \ep
> >>> +
> >>> +	mov	\ep, #0
> >>> +	eret
> >>>  .endm
> >>>
> >>>  #if defined(CONFIG_GICV3)
> >>> diff --git a/arch/arm/include/asm/system.h
> >>> b/arch/arm/include/asm/system.h index 9ae890a..0271ddb 100644
> >>> --- a/arch/arm/include/asm/system.h
> >>> +++ b/arch/arm/include/asm/system.h
> >>> @@ -17,6 +17,102 @@
> >>>  #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
> >>> +
> >>> +/*
> >>> + * SCR_EL3 bits definitions
> >>> + */
> >>> +#define SCR_EL3_RW_AARCH64	(1 << 10) /* Next lower level is
> AArch64
> >> */
> >>> +#define SCR_EL3_RW_AARCH32	(0 << 10) /* Lower lowers level are
> >> AArch32  */
> >>> +#define SCR_EL3_HCE_EN		(1 << 8)  /* Hypervisor Call enable
> >> */
> >>> +#define SCR_EL3_SMD_DIS		(1 << 7)  /* Secure Monitor Call
> >> disable     */
> >>> +#define SCR_EL3_BIT5_4_RES1	(3 << 4)  /* Reserved, RES1
> >> */
> >>> +#define SCR_EL3_NS_EN		(1 << 0)  /* EL0 and EL1 in Non-
> scure
> >> state  */
> >>> +
> >>> +/*
> >>> + * SPSR_EL3/SPSR_EL2 bits definitions  */
> >>> +#define SPSR_EL_END_LE		(0 << 9)  /* Exception Little-endian
> >> */
> >>> +#define SPSR_EL_DEBUG_MASK	(1 << 9)  /* Debug exception masked
> >> */
> >>> +#define SPSR_EL_ASYN_MASK	(1 << 8)  /* Asynchronous data abort
> >> masked   */
> >>> +#define SPSR_EL_SERR_MASK	(1 << 8)  /* System Error exception masked
> >> */
> >>> +#define SPSR_EL_IRQ_MASK	(1 << 7)  /* IRQ exception masked
> >> */
> >>> +#define SPSR_EL_FIQ_MASK	(1 << 6)  /* FIQ exception masked
> >> */
> >>> +#define SPSR_EL_T_A32		(0 << 5)  /* AArch32 instruction set
> A32
> >> */
> >>> +#define SPSR_EL_M_AARCH64	(0 << 4)  /* Exception taken from AArch64
> >> */
> >>> +#define SPSR_EL_M_AARCH32	(1 << 4)  /* Exception taken from AArch32
> >> */
> >>> +#define SPSR_EL_M_SVC		(0x3)     /* Exception taken from
> SVC mode
> >> */
> >>> +#define SPSR_EL_M_HYP		(0xa)     /* Exception taken from
> HYP mode
> >> */
> >>> +#define SPSR_EL_M_EL1H		(5)       /* Exception taken from
> >> EL1h mode   */
> >>> +#define SPSR_EL_M_EL2H		(9)       /* Exception taken from
> >> EL2h mode   */
> >>> +
> >>> +/*
> >>> + * CPTR_EL2 bits definitions
> >>> + */
> >>> +#define CPTR_EL2_BIT13_12_RES1	(3 << 12) /* Reserved, RES1
> >> */
> >>> +#define CPTR_EL2_BIT9_0_RES1	(0x3ff)   /* Reserved, RES1
> >> */
> >>> +
> >>> +/*
> >>> + * SCTLR_EL2 bits definitions
> >>> + */
> >>> +#define SCTLR_EL2_BIT29_28_RES1	(3 << 28) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL2_EE_LE		(0 << 25) /* Exception Little-endian
> >> */
> >>> +#define SCTLR_EL2_BIT23_22_RES1	(3 << 22) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL2_WXN_DIS	(0 << 19) /* Write permission is not XN
> >> */
> >>> +#define SCTLR_EL2_BIT18_RES1	(1 << 18) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL2_BIT16_RES1	(1 << 16) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL2_ICACHE_DIS	(0 << 12) /* Instruction cache
> >> disabled       */
> >>> +#define SCTLR_EL2_BIT11_RES1	(1 << 11) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL2_BIT5_4_RES1	(3 << 4)  /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL2_SA_DIS	(0 << 3)  /* Stack Alignment Check
> >> disabled   */
> >>> +#define SCTLR_EL2_DCACHE_DIS	(0 << 2)  /* Data cache disabled
> >> */
> >>> +#define SCTLR_EL2_ALIGN_DIS	(0 << 1)  /* Alignment check
> disabled
> >> */
> >>> +#define SCTLR_EL2_MMU_DIS	(0)       /* MMU disabled
> >> */
> >>> +
> >>> +/*
> >>> + * CNTHCTL_EL2 bits definitions
> >>> + */
> >>> +#define CNTHCTL_EL2_EL1PCEN_EN	(1 << 1)  /* Physical timer regs
> >> accessible   */
> >>> +#define CNTHCTL_EL2_EL1PCTEN_EN	(1 << 0)  /* Physical counter
> >> accessible      */
> >>> +
> >>> +/*
> >>> + * HCR_EL2 bits definitions
> >>> + */
> >>> +#define HCR_EL2_RW_AARCH64	(1 << 31) /* EL1 is AArch64
> >> */
> >>> +#define HCR_EL2_RW_AARCH32	(0 << 31) /* Lower levels are
> AArch32
> >> */
> >>> +#define HCR_EL2_HCD_DIS		(1 << 29) /* Hypervisor Call
> >> disabled         */
> >>> +
> >>> +/*
> >>> + * CPACR_EL1 bits definitions
> >>> + */
> >>> +#define CPACR_EL1_FPEN_EN	(3 << 20) /* SIMD and FP instruction
> >> enabled  */
> >>> +
> >>> +/*
> >>> + * SCTLR_EL1 bits definitions
> >>> + */
> >>> +#define SCTLR_EL1_BIT29_28_RES1	(3 << 28) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL1_UCI_DIS	(0 << 26) /* Cache instruction disabled
> >> */
> >>> +#define SCTLR_EL1_EE_LE		(0 << 25) /* Exception Little-endian
> >> */
> >>> +#define SCTLR_EL1_BIT23_22_RES1	(3 << 22) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL1_BIT20_RES1	(1 << 20) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL1_WXN_DIS	(0 << 19) /* Write permission is not XN
> >> */
> >>> +#define SCTLR_EL1_NTWE_DIS	(0 << 18) /* WFE instruction
> disabled
> >> */
> >>> +#define SCTLR_EL1_NTWI_DIS	(0 << 16) /* WFI instruction
> disabled
> >> */
> >>> +#define SCTLR_EL1_UCT_DIS	(0 << 15) /* CTR_EL0 access disabled
> >> */
> >>> +#define SCTLR_EL1_DZE_DIS	(0 << 14) /* DC ZVA instruction disabled
> >> */
> >>> +#define SCTLR_EL1_ICACHE_DIS	(0 << 12) /* Instruction cache
> >> disabled       */
> >>> +#define SCTLR_EL1_BIT11_RES1	(1 << 11) /* Reserved, RES1
> >> */
> >>> +#define SCTLR_EL1_UMA_DIS	(0 << 9)  /* User Mask Access disabled
> >> */
> >>> +#define SCTLR_EL1_SED_EN	(0 << 8)  /* SETEND instruction enabled
> >> */
> >>> +#define SCTLR_EL1_ITD_EN	(0 << 7)  /* IT instruction enabled
> >> */
> >>> +#define SCTLR_EL1_CP15BEN_DIS	(0 << 5)  /* CP15 barrier operation
> >> disabled  */
> >>> +#define SCTLR_EL1_SA0_DIS	(0 << 4)  /* Stack Alignment EL0 disabled
> >> */
> >>> +#define SCTLR_EL1_SA_DIS	(0 << 3)  /* Stack Alignment EL1 disabled
> >> */
> >>> +#define SCTLR_EL1_DCACHE_DIS	(0 << 2)  /* Data cache disabled
> >> */
> >>> +#define SCTLR_EL1_ALIGN_DIS	(0 << 1)  /* Alignment check
> disabled
> >> */
> >>> +#define SCTLR_EL1_MMU_DIS	(0)       /* MMU disabled
> >> */
> >>> +
> >>>  #ifndef __ASSEMBLY__
> >>>
> >>>  u64 get_page_table_size(void);
> >>> @@ -100,8 +196,26 @@ 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);
> >>>  void gic_init(void);
> >>>  void gic_send_sgi(unsigned long sgino);  void
> >>> wait_for_wakeup(void); diff --git a/arch/arm/lib/bootm.c
> >>> b/arch/arm/lib/bootm.c index 0838d89..1bbf85c 100644
> >>> --- a/arch/arm/lib/bootm.c
> >>> +++ b/arch/arm/lib/bootm.c
> >>> @@ -189,13 +189,19 @@ static void setup_end_tag(bd_t *bd)  __weak
> >>> void setup_board_tags(struct tag **in_params) {}
> >>>
> >>>  #ifdef CONFIG_ARM64
> >>> -static void do_nonsec_virt_switch(void)
> >>> +static void do_nonsec_virt_switch(bootm_headers_t *images, int
> >>> +flag)
> >>>  {
> >>>  	smp_kick_all_cpus();
> >>>  	dcache_disable();	/* flush cache before swtiching to EL2 */
> >>> -	armv8_switch_to_el2();
> >>> +
> >>>  #ifdef CONFIG_ARMV8_SWITCH_TO_EL1
> >>> -	armv8_switch_to_el1();
> >>> +	armv8_switch_to_el2((u64)images->ep, (u64)gd->bd->bi_arch_number,
> >>> +			    (u64)images->ft_addr, ES_TO_AARCH64);
> >>> +	armv8_switch_to_el1((u64)images->ep, (u64)gd->bd->bi_arch_number,
> >>> +			    (u64)images->ft_addr, flag); #else
> >>> +	armv8_switch_to_el2((u64)images->ep, (u64)gd->bd->bi_arch_number,
> >>> +			    (u64)images->ft_addr, flag);
> >>>  #endif
> >>>  }
> >>>  #endif
> >>> @@ -275,6 +281,7 @@ static void boot_jump_linux(bootm_headers_t
> >> *images, int flag)
> >>>  	void (*kernel_entry)(void *fdt_addr, void *res0, void *res1,
> >>>  			void *res2);
> >>>  	int fake = (flag & BOOTM_STATE_OS_FAKE_GO);
> >>> +	int es_flag = ES_TO_AARCH64;
> >>>
> >>>  	kernel_entry = (void (*)(void *fdt_addr, void *res0, void *res1,
> >>>  				void *res2))images->ep;
> >>> @@ -286,7 +293,11 @@ static void boot_jump_linux(bootm_headers_t
> >> *images, int flag)
> >>>  	announce_and_cleanup(fake);
> >>>
> >>>  	if (!fake) {
> >>> -		do_nonsec_virt_switch();
> >>> +		if ((IH_ARCH_DEFAULT == IH_ARCH_ARM64) &&
> >>> +		    (images->os.arch == IH_ARCH_ARM))
> >>> +			es_flag = ES_TO_AARCH32;
> >>> +
> >>> +		do_nonsec_virt_switch(images, es_flag);
> >>>  		kernel_entry(images->ft_addr, NULL, NULL, NULL);
> >>>  	}
> >>>  #else
> >>> diff --git a/common/image-fit.c b/common/image-fit.c index
> >>> 9873957..982021b 100644
> >>> --- a/common/image-fit.c
> >>> +++ b/common/image-fit.c
> >>> @@ -26,6 +26,7 @@ DECLARE_GLOBAL_DATA_PTR;  #include <u-boot/md5.h>
> >>> #include <u-boot/sha1.h>  #include <u-boot/sha256.h>
> >>> +#include <generated/autoconf.h>
> >>>
> >>>
> >>> /*******************************************************************
> >>> **
> >>> ********/
> >>>  /* New uImage format routines */
> >>> @@ -1164,7 +1165,9 @@ 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 &&
> >>> +		 CONFIG_ARM64_SUPPORT_AARCH32);
> >>
> >> Uh, I think this define is simply not defined for non-compatible
> >> systems (including non-arm64). This really needs to go into an #ifdef.
> > [Alison Wang] I think arch == IH_ARCH_ARM64 will check for non-arm64
> system.
> > I can't understand your concern. Please explain more.
> 
> You either get a
> 
> #define CONFIG_ARM64_SUPPORT_AARCH32 1
> 
> in the config header if the option is set or simply nothing at all. If
> there's nothing, compiling this code will result in an unresolved symbol.
> 
[Alison Wang] Yes, I will change as follows in the next version.

int fit_image_check_arch(const void *fit, int noffset, uint8_t arch)
 {
        uint8_t image_arch;
+       int aarch32_support = 0;
+
+#ifdef CONFIG_ARM64_SUPPORT_AARCH32
+       aarch32_support = 1;
+#endif

        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_ARM64 && image_arch == IH_ARCH_ARM &&
-                CONFIG_ARM64_SUPPORT_AARCH32);
+                aarch32_support);
 }


Best Regards,
Alison Wang


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