On 13.05.16 10:40, 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
arch/arm/cpu/armv8/transition.S | 100 ++++++++++++++++++++++++++++++++++++++++ arch/arm/include/asm/system.h | 2 + arch/arm/lib/bootm.c | 20 +++++++- common/image-fit.c | 12 ++++- 4 files changed, 131 insertions(+), 3 deletions(-)
diff --git a/arch/arm/cpu/armv8/transition.S b/arch/arm/cpu/armv8/transition.S index 253a39b..9d7a17a 100644 --- a/arch/arm/cpu/armv8/transition.S +++ b/arch/arm/cpu/armv8/transition.S @@ -21,3 +21,103 @@ ENTRY(armv8_switch_to_el1) 0: ret 1: armv8_switch_to_el1_m x0, x1 ENDPROC(armv8_switch_to_el1)
+/*
- x0: kernel entry point
- x1: machine nr
- x2: fdt address
- */
+ENTRY(armv8_switch_to_el2_aarch32)
- switch_el x3, 1f, 0f, 0f
+0: ret +1:
- mov x7, x0
- mov x8, x1
- mov x9, x2
- /* 32bit EL2 | HCE | SMD | RES1 (Bits[5:4]) | Non-secure EL0/EL1 */
- mov x1, 0x1b1
- msr scr_el3, x1
- msr cptr_el3, xzr /* Disable coprocessor traps to EL3 */
- mov x1, 0x33ff
- msr cptr_el2, x1 /* Disable coprocessor traps to EL2 */
- /* Initialize Generic Timers */
- msr cntvoff_el2, xzr
- mov x1, #0x0830
- movk x1, #0x30c5, lsl #16
- msr sctlr_el2, x1
Why is this necessary?
- /* Return to AArch32 Hypervisor mode */
- mov x1, sp
- msr sp_el2, x1
- mrs x1, vbar_el3
- msr vbar_el2, x1 /* Migrate VBAR */
- mov x1, #0x1da
- msr spsr_el3, x1
- msr elr_el3, x7
- mov x0, #0
- mov x1, x8
- mov x2, x9
- eret
+ENDPROC(armv8_switch_to_el2_aarch32)
This whole thing looks like a copy of armv8_switch_to_el2_m. Just parameterize that one and put the few bits that are different in macro ifs.
+/*
- x0: kernel entry point
- x1: machine nr
- x2: fdt address
- */
+ENTRY(armv8_switch_to_el1_aarch32)
- switch_el x3, 0f, 1f, 0f
+0: ret +1:
- mov x7, x0
- mov x8, x1
- mov x9, x2
- /* Initialize Generic Timers */
- mrs x0, cnthctl_el2
- orr x0, x0, #0x3 /* Enable EL1 access to timers */
- msr cnthctl_el2, x0
- msr cntvoff_el2, xzr
/* Initialize MPID/MPIDR registers */- mrs x0, midr_el1
- mrs x1, mpidr_el1
- msr vpidr_el2, x0
- msr vmpidr_el2, x1
/* Disable coprocessor traps */- mov x0, #0x33ff
- msr cptr_el2, x0 /* Disable coprocessor traps to EL2 */
msr hstr_el2, xzr /* Disable coprocessor traps to EL2 */mov x0, #3 << 20msr cpacr_el1, x0 /* Enable FP/SIMD at EL1 */- /* Initialize HCR_EL2 */
- mov x0, #(0 << 31) /* 32bit EL1 */
- orr x0, x0, #(1 << 29) /* Disable HVC */
- msr hcr_el2, x0
- mov x0, #0x0800
- movk x0, #0x30d0, lsl #16
- msr sctlr_el1, x0
- /* Return to AArch32 Supervisor mode */
- mov x0, sp
- msr sp_el1, x0 /* Migrate SP */
- mrs x0, vbar_el2
- msr vbar_el1, x0 /* Migrate VBAR */
- mov x0, #0x1d3
- msr spsr_el2, x0
- msr elr_el2, x7
- mov x0, #0
- mov x1, x8
- mov x2, x9
- eret
+ENDPROC(armv8_switch_to_el1_aarch32)
Does anybody really care about jumping to el1?
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 9ae890a..bb87cf0 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -102,6 +102,8 @@ void __asm_switch_ttbr(u64 new_ttbr);
void armv8_switch_to_el2(void); void armv8_switch_to_el1(void); +void armv8_switch_to_el2_aarch32(u64 entry_point, u64 mach_nr, u64 fdt_addr); +void armv8_switch_to_el1_aarch32(u64 entry_point, u64 mach_nr, u64 fdt_addr); 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..a39c3d2 100644 --- a/arch/arm/lib/bootm.c +++ b/arch/arm/lib/bootm.c @@ -286,8 +286,24 @@ 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();+#ifdef CONFIG_ARMV8_SWITCH_TO_EL1
armv8_switch_to_el2();armv8_switch_to_el1_aarch32((u64)images->ep,(u64)gd->bd->bi_arch_number,(u64)images->ft_addr);+#else
armv8_switch_to_el2_aarch32((u64)images->ep,(u64)gd->bd->bi_arch_number,(u64)images->ft_addr);+#endif
Does this compile on 32bit targets?
Alex