On Fri, Mar 21, 2025 at 10:32:58AM +0000, Frediano Ziglio wrote:
> Although code is compiled with -fpic option data is not position
> independent. This causes data pointer to become invalid if
> code is not relocated properly which is what happens for
> efi_multiboot2 which is called by multiboot entry code.
>
> Code tested adding
> PrintErrMesg(L"Test message", EFI_BUFFER_TOO_SMALL);
> in efi_multiboot2 before calling efi_arch_edd (this function
> can potentially call PrintErrMesg).
>
> Before the patch (XenServer installation on Qemu, xen replaced
> with vanilla xen.gz):
> Booting `XenServer (Serial)'Booting `XenServer (Serial)'
> Test message: !!!! X64 Exception Type - 0E(#PF - Page-Fault) CPU Apic ID -
> 00000000 !!!!
> ExceptionData - 0000000000000000 I:0 R:0 U:0 W:0 P:0 PK:0 SS:0 SGX:0
> RIP - 000000007EE21E9A, CS - 0000000000000038, RFLAGS - 0000000000210246
> RAX - 000000007FF0C1B5, RCX - 0000000000000050, RDX - 0000000000000010
> RBX - 0000000000000000, RSP - 000000007FF0C180, RBP - 000000007FF0C210
> RSI - FFFF82D040467CE8, RDI - 0000000000000000
> R8 - 000000007FF0C1C8, R9 - 000000007FF0C1C0, R10 - 0000000000000000
> R11 - 0000000000001020, R12 - FFFF82D040467CE8, R13 - 000000007FF0C1B8
> R14 - 000000007EA33328, R15 - 000000007EA332D8
> DS - 0000000000000030, ES - 0000000000000030, FS - 0000000000000030
> GS - 0000000000000030, SS - 0000000000000030
> CR0 - 0000000080010033, CR2 - FFFF82D040467CE8, CR3 - 000000007FC01000
> CR4 - 0000000000000668, CR8 - 0000000000000000
> DR0 - 0000000000000000, DR1 - 0000000000000000, DR2 - 0000000000000000
> DR3 - 0000000000000000, DR6 - 00000000FFFF0FF0, DR7 - 0000000000000400
> GDTR - 000000007F9DB000 0000000000000047, LDTR - 0000000000000000
> IDTR - 000000007F48E018 0000000000000FFF, TR - 0000000000000000
> FXSAVE_STATE - 000000007FF0BDE0
> !!!! Find image based on IP(0x7EE21E9A) (No PDB)
> (ImageBase=000000007EE20000, EntryPoint=000000007EE23935) !!!!
>
> After the patch:
> Booting `XenServer (Serial)'Booting `XenServer (Serial)'
> Test message: Buffer too small
> BdsDxe: loading Boot0000 "UiApp" from
> Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
> BdsDxe: starting Boot0000 "UiApp" from
> Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
>
> This partially rollback commit 00d5d5ce23e6.
>
> Fixes: 9180f5365524 ("x86: add multiboot2 protocol support for EFI platforms")
> Signed-off-by: Frediano Ziglio <[email protected]>-no-jump-tables is available since clang 3.9.0 (and since GCC 4.1.0), so with upgraded base toolchain requirements it's safe to commit this now. Acked-by: Marek Marczykowski-Górecki <[email protected]> > --- > Changes since v1: > - added "Fixes:" tag; > - fixed cast style change. > > Changes since v2: > - wrap long line. > > Changes since v3: > - fixed "Fixes:" tag. > > Changes since v4: > - use switch instead of tables. > > Changes since v5: > - added -fno-jump-tables option. > > Changes since v6: > - rebased. > --- > xen/common/efi/boot.c | 58 ++++++++++++++++++++++++------------ > xen/common/efi/efi-common.mk | 1 + > 2 files changed, 40 insertions(+), 19 deletions(-) > > diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c > index efbec00af9..143b5681ba 100644 > --- a/xen/common/efi/boot.c > +++ b/xen/common/efi/boot.c > @@ -287,33 +287,53 @@ static bool __init match_guid(const EFI_GUID *guid1, > const EFI_GUID *guid2) > /* generic routine for printing error messages */ > static void __init PrintErrMesg(const CHAR16 *mesg, EFI_STATUS ErrCode) > { > - static const CHAR16* const ErrCodeToStr[] __initconstrel = { > - [~EFI_ERROR_MASK & EFI_NOT_FOUND] = L"Not found", > - [~EFI_ERROR_MASK & EFI_NO_MEDIA] = L"The device has no > media", > - [~EFI_ERROR_MASK & EFI_MEDIA_CHANGED] = L"Media changed", > - [~EFI_ERROR_MASK & EFI_DEVICE_ERROR] = L"Device error", > - [~EFI_ERROR_MASK & EFI_VOLUME_CORRUPTED] = L"Volume corrupted", > - [~EFI_ERROR_MASK & EFI_ACCESS_DENIED] = L"Access denied", > - [~EFI_ERROR_MASK & EFI_OUT_OF_RESOURCES] = L"Out of resources", > - [~EFI_ERROR_MASK & EFI_VOLUME_FULL] = L"Volume is full", > - [~EFI_ERROR_MASK & EFI_SECURITY_VIOLATION] = L"Security violation", > - [~EFI_ERROR_MASK & EFI_CRC_ERROR] = L"CRC error", > - [~EFI_ERROR_MASK & EFI_COMPROMISED_DATA] = L"Compromised data", > - [~EFI_ERROR_MASK & EFI_BUFFER_TOO_SMALL] = L"Buffer too small", > - }; > - EFI_STATUS ErrIdx = ErrCode & ~EFI_ERROR_MASK; > - > StdOut = StdErr; > PrintErr(mesg); > PrintErr(L": "); > > - if( (ErrIdx < ARRAY_SIZE(ErrCodeToStr)) && ErrCodeToStr[ErrIdx] ) > - mesg = ErrCodeToStr[ErrIdx]; > - else > + switch (ErrCode) > { > + case EFI_NOT_FOUND: > + mesg = L"Not found"; > + break; > + case EFI_NO_MEDIA: > + mesg = L"The device has no media"; > + break; > + case EFI_MEDIA_CHANGED: > + mesg = L"Media changed"; > + break; > + case EFI_DEVICE_ERROR: > + mesg = L"Device error"; > + break; > + case EFI_VOLUME_CORRUPTED: > + mesg = L"Volume corrupted"; > + break; > + case EFI_ACCESS_DENIED: > + mesg = L"Access denied"; > + break; > + case EFI_OUT_OF_RESOURCES: > + mesg = L"Out of resources"; > + break; > + case EFI_VOLUME_FULL: > + mesg = L"Volume is full"; > + break; > + case EFI_SECURITY_VIOLATION: > + mesg = L"Security violation"; > + break; > + case EFI_CRC_ERROR: > + mesg = L"CRC error"; > + break; > + case EFI_COMPROMISED_DATA: > + mesg = L"Compromised data"; > + break; > + case EFI_BUFFER_TOO_SMALL: > + mesg = L"Buffer too small"; > + break; > + default: > PrintErr(L"ErrCode: "); > DisplayUint(ErrCode, 0); > mesg = NULL; > + break; > } > blexit(mesg); > } > diff --git a/xen/common/efi/efi-common.mk b/xen/common/efi/efi-common.mk > index 23cafcf20c..06b1c19674 100644 > --- a/xen/common/efi/efi-common.mk > +++ b/xen/common/efi/efi-common.mk > @@ -2,6 +2,7 @@ EFIOBJ-y := boot.init.o pe.init.o ebmalloc.o runtime.o > EFIOBJ-$(CONFIG_COMPAT) += compat.o > > CFLAGS-y += -fshort-wchar > +CFLAGS-y += -fno-jump-tables > CFLAGS-y += -iquote $(srctree)/common/efi > CFLAGS-y += -iquote $(srcdir) > > -- > 2.43.0 > -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab
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