Author: andrew
Date: Tue Oct 13 16:51:05 2020
New Revision: 366670
URL: https://svnweb.freebsd.org/changeset/base/366670
Log:
Use adrp in the arm64 efi loader
On startup the arm64 efi loaders need to know PC-relative addresses.
Previously we used the adr instruction to find this address, however this
instruction is limited to +/- 1MiB.
Switch to adrp to find the 4k page the address is within and an add to
set the bottom 12 bits. This lets us address +/- 4GiB which should be
large enough for now.
Reported by: imp
MFC after: 2 weeks
Sponsored by: Innovate UK
Modified:
head/stand/efi/loader/arch/arm64/start.S
Modified: head/stand/efi/loader/arch/arm64/start.S
==============================================================================
--- head/stand/efi/loader/arch/arm64/start.S Tue Oct 13 16:19:21 2020
(r366669)
+++ head/stand/efi/loader/arch/arm64/start.S Tue Oct 13 16:51:05 2020
(r366670)
@@ -142,8 +142,10 @@ _start:
/* Save the boot params to the stack */
stp x0, x1, [sp, #-16]!
- adr x0, __bss_start
- adr x1, __bss_end
+ adrp x0, __bss_start
+ add x0, x0, :lo12:__bss_start
+ adrp x1, __bss_end
+ add x1, x1, :lo12:__bss_end
b 2f
@@ -153,8 +155,10 @@ _start:
cmp x0, x1
b.lo 1b
- adr x0, ImageBase
- adr x1, _DYNAMIC
+ adrp x0, ImageBase
+ add x0, x0, :lo12:ImageBase
+ adrp x1, _DYNAMIC
+ add x1, x1, :lo12:_DYNAMIC
bl self_reloc
@@ -165,7 +169,8 @@ _start:
* Load the stack to use. The default stack may be too small for
* the lua loader.
*/
- adr x2, initstack_end
+ adrp x2, initstack_end
+ add x2, x2, :lo12:initstack_end
mov sp, x2
#endif
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