> On Jul 14, 2023, at 4:29 AM, Shaoqin Huang <shahuang@xxxxxxxxxx> wrote: > > !! External Email > > Hi, > > On 7/14/23 18:31, Alexandru Elisei wrote: >> Hi, >> >> On Sat, Jun 17, 2023 at 01:31:37AM +0000, Nadav Amit wrote: >>> From: Nadav Amit <namit@xxxxxxxxxx> >>> >>> Do not assume PAN is not supported or that sctlr_el1.SPAN is already set. >> >> In arm/cstart64.S >> >> .globl start >> start: >> /* get our base address */ >> [..] >> >> 1: >> /* zero BSS */ >> [..] >> >> /* zero and set up stack */ >> [..] >> >> /* set SCTLR_EL1 to a known value */ >> ldr x4, =INIT_SCTLR_EL1_MMU_OFF >> [..] >> >> /* set up exception handling */ >> bl exceptions_init >> [..] >> >> Where in lib/arm64/asm/sysreg.h: >> >> #define SCTLR_EL1_RES1 (_BITUL(7) | _BITUL(8) | _BITUL(11) | _BITUL(20) | \ >> _BITUL(22) | _BITUL(23) | _BITUL(28) | _BITUL(29)) >> #define INIT_SCTLR_EL1_MMU_OFF \ >> SCTLR_EL1_RES1 >> >> Look like bit 23 (SPAN) should be set. >> >> How are you seeing SCTLR_EL1.SPAN unset? > > Yeah. the sctlr_el1.SPAN has always been set by the above flow. So Nadav > you can describe what you encounter with more details. Like which tests > crash you encounter, and how to reproduce it. I am using Nikos’s work to run the test using EFI, not from QEMU. So the code that you mentioned - which is supposed to initialize SCTLR - is not executed (and actually not part of the EFI image). Note that using EFI, the entry point is _start [1], and not “start”. That is also the reason lack of BSS zeroing also caused me issues with the EFI setup, which I reported before. [1] https://gitlab.com/kvm-unit-tests/kvm-unit-tests/-/blob/master/arm/efi/crt0-efi-aarch64.S#L113
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