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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen/arm64: head.S: Introduce macro to load the physical address of a symbol
On Thu, 7 Dec 2017, Julien Grall wrote:
> A lot of places in the ARM64 assembly code requiring to load the
> physical address of a symbol. Rather than open-coding the translation,
> introduce a new macro that will load the physical address of a symbol.
>
> Lastly, use this new macro to replace all the current opencoded version.
>
> Note that most of comments associated to the code changed have been
> removed because the code is now self-explanatory.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> ---
> xen/arch/arm/arm64/head.S | 48
> ++++++++++++++++++++---------------------------
> 1 file changed, 20 insertions(+), 28 deletions(-)
>
> diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
> index 78292f4396..fa0ef7034c 100644
> --- a/xen/arch/arm/arm64/head.S
> +++ b/xen/arch/arm/arm64/head.S
> @@ -85,6 +85,12 @@
> #define PRINT(s)
> #endif /* !CONFIG_EARLY_PRINTK */
>
> +/* Load the physical address of a symbol into xb */
> +.macro load_paddr xb, sym
> + ldr \xb, =\sym
> + add \xb, \xb, x20
> +.endm
> +
> /*.aarch64*/
>
> /*
> @@ -247,8 +253,7 @@ real_start_efi:
>
> /* Using the DTB in the .dtb section? */
> #ifdef CONFIG_DTB_FILE
> - ldr x21, =_sdtb
> - add x21, x21, x20 /* x21 := paddr(DTB) */
> + load_paddr x21, _sdtb
> #endif
>
> mov x22, #0 /* x22 := is_secondary_cpu */
> @@ -281,8 +286,7 @@ common_start:
> /* Non-boot CPUs wait here until __cpu_up is ready for them */
> cbz x22, 1f
>
> - ldr x0, =smp_up_cpu
> - add x0, x0, x20 /* Apply physical offset */
> + load_paddr x0, smp_up_cpu
> dsb sy
> 2: ldr x1, [x0]
> cmp x1, x24
> @@ -323,10 +327,8 @@ el2: PRINT("- Xen starting at EL2 -\r\n")
> cbnz x26, skip_bss
>
> PRINT("- Zero BSS -\r\n")
> - ldr x0, =__bss_start /* Load start & end of bss */
> - ldr x1, =__bss_end
> - add x0, x0, x20 /* Apply physical offset */
> - add x1, x1, x20
> + load_paddr x0, __bss_start /* Load paddr of start & end of bss */
> + load_paddr x1, __bss_end
>
> 1: str xzr, [x0], #8
> cmp x0, x1
> @@ -386,13 +388,11 @@ skip_bss:
> cset x25, eq /* x25 := identity map in place, or not
> */
>
> /* Write Xen's PT's paddr into TTBR0_EL2 */
> - ldr x4, =boot_pgtable
> - add x4, x4, x20 /* x4 := paddr (boot_pagetable) */
> + load_paddr x4, boot_pgtable
> msr TTBR0_EL2, x4
>
> /* Setup boot_pgtable: */
> - ldr x1, =boot_first
> - add x1, x1, x20 /* x1 := paddr (boot_first) */
> + load_paddr x1, boot_first
>
> /* ... map boot_first in boot_pgtable[0] */
> mov x3, #PT_PT /* x2 := table map of boot_first */
> @@ -407,16 +407,14 @@ skip_bss:
> /* Level zero does not support superpage mappings, so we have
> * to use an extra first level page in which we create a 1GB mapping.
> */
> - ldr x2, =boot_first_id
> - add x2, x2, x20 /* x2 := paddr (boot_first_id) */
> + load_paddr x2, boot_first_id
>
> mov x3, #PT_PT /* x2 := table map of boot_first_id */
> orr x2, x2, x3 /* + rights for linear PT */
> lsl x1, x1, #3 /* x1 := Slot offset */
> str x2, [x4, x1]
>
> - ldr x4, =boot_first_id /* Next level into boot_first_id */
> - add x4, x4, x20 /* x4 := paddr(boot_first_id) */
> + load_paddr x4, boot_first_id
>
> lsr x1, x19, #FIRST_SHIFT /* x1 := Offset of base paddr in
> boot_first_id */
> lsl x2, x1, #FIRST_SHIFT /* x2 := Base address for 1GB mapping */
> @@ -428,12 +426,10 @@ skip_bss:
> mov x25, #1 /* x25 := identity map now in place */
>
> 1: /* Setup boot_first: */
> - ldr x4, =boot_first /* Next level into boot_first */
> - add x4, x4, x20 /* x4 := paddr(boot_first) */
> + load_paddr x4, boot_first /* Next level into boot_first */
>
> /* ... map boot_second in boot_first[0] */
> - ldr x1, =boot_second
> - add x1, x1, x20 /* x1 := paddr(boot_second) */
> + load_paddr x1, boot_second
> mov x3, #PT_PT /* x2 := table map of boot_second */
> orr x2, x1, x3 /* + rights for linear PT */
> str x2, [x4, #0] /* Map it in slot 0 */
> @@ -452,12 +448,10 @@ skip_bss:
> mov x25, #1 /* x25 := identity map now in place */
>
> 1: /* Setup boot_second: */
> - ldr x4, =boot_second /* Next level into boot_second */
> - add x4, x4, x20 /* x4 := paddr(boot_second) */
> + load_paddr x4, boot_second
>
> /* ... map boot_third in boot_second[1] */
> - ldr x1, =boot_third
> - add x1, x1, x20 /* x1 := paddr(boot_third) */
> + load_paddr x1, boot_third
> mov x3, #PT_PT /* x2 := table map of boot_third */
> orr x2, x1, x3 /* + rights for linear PT */
> str x2, [x4, #8] /* Map it in slot 1 */
> @@ -477,8 +471,7 @@ skip_bss:
> mov x25, #1 /* x25 := identity map now in place */
>
> 1: /* Setup boot_third: */
> - ldr x4, =boot_third
> - add x4, x4, x20 /* x4 := paddr (boot_third) */
> + load_paddr x4, boot_third
>
> lsr x2, x19, #THIRD_SHIFT /* Base address for 4K mapping */
> lsl x2, x2, #THIRD_SHIFT
> @@ -538,8 +531,7 @@ paging:
>
> /* Map fixmap into boot_second */
> ldr x4, =boot_second /* x4 := vaddr (boot_second) */
> - ldr x2, =xen_fixmap
> - add x2, x2, x20 /* x2 := paddr (xen_fixmap) */
> + load_paddr x2, xen_fixmap
> mov x3, #PT_PT
> orr x2, x2, x3 /* x2 := table map of xen_fixmap */
> ldr x1, =FIXMAP_ADDR(0)
> --
> 2.11.0
>
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