|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3] xen: Work around Clang generating .data.rel.ro section for init-only files
On Wed, 24 Feb 2016, Jan Beulich wrote:
> >>> On 23.02.16 at 19:36, <andrew.cooper3@xxxxxxxxxx> wrote:
> > Clang-3.8 generates several .data.rel.ro sections when compiling Xen. As
> > these contain no global symbols, they should be .data.rel.ro.local. This
> > breaks the SPECIAL_DATA_SECTIONS check when converting the transition units
> > to
> > being init-only.
> >
> > For alternatives.c, explicitly move the nops arrays into __initconst. For
> > efi
> > boot.c, manually create the optimisation performed by Clang by collapsing
> > the
> > switch statement into a lookup table. The double use of const is required
> > to
> > avoid breaking the ARM build by creating a section type conflict with
> > fdt_guid.
> >
> > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> > ---
> > CC: Jan Beulich <JBeulich@xxxxxxxx>
>
> Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > v2: Fix ARM build
> > v3: Introduce and use __initconstrel
> > ---
> > xen/arch/arm/xen.lds.S | 1 +
> > xen/arch/x86/alternative.c | 4 ++--
> > xen/arch/x86/xen.lds.S | 1 +
> > xen/common/efi/boot.c | 58
> > +++++++++++++++-------------------------------
> > xen/include/xen/init.h | 1 +
> > 5 files changed, 24 insertions(+), 41 deletions(-)
> >
> > diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
> > index f501a2f..9f7f915 100644
> > --- a/xen/arch/arm/xen.lds.S
> > +++ b/xen/arch/arm/xen.lds.S
> > @@ -114,6 +114,7 @@ SECTIONS
> > . = ALIGN(PAGE_SIZE);
> > .init.data : {
> > *(.init.rodata)
> > + *(.init.rodata.rel)
> > *(.init.rodata.str*)
> > *(.init.data)
> > *(.init.data.rel)
> > diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c
> > index 46ac0fd..9d54df1 100644
> > --- a/xen/arch/x86/alternative.c
> > +++ b/xen/arch/x86/alternative.c
> > @@ -38,7 +38,7 @@ static const unsigned char k8nops[] __initconst = {
> > K8_NOP7,
> > K8_NOP8
> > };
> > -static const unsigned char * const k8_nops[ASM_NOP_MAX+1] = {
> > +static const unsigned char * const k8_nops[ASM_NOP_MAX+1] __initconstrel =
> > {
> > NULL,
> > k8nops,
> > k8nops + 1,
> > @@ -62,7 +62,7 @@ static const unsigned char p6nops[] __initconst = {
> > P6_NOP7,
> > P6_NOP8
> > };
> > -static const unsigned char * const p6_nops[ASM_NOP_MAX+1] = {
> > +static const unsigned char * const p6_nops[ASM_NOP_MAX+1] __initconstrel =
> > {
> > NULL,
> > p6nops,
> > p6nops + 1,
> > diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
> > index 9fde1db..b3eb207 100644
> > --- a/xen/arch/x86/xen.lds.S
> > +++ b/xen/arch/x86/xen.lds.S
> > @@ -119,6 +119,7 @@ SECTIONS
> > } :text
> > .init.data : {
> > *(.init.rodata)
> > + *(.init.rodata.rel)
> > *(.init.rodata.str*)
> > *(.init.data)
> > *(.init.data.rel)
> > diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
> > index 53c7452..125c9ce 100644
> > --- a/xen/common/efi/boot.c
> > +++ b/xen/common/efi/boot.c
> > @@ -241,53 +241,33 @@ static void __init noreturn blexit(const CHAR16 *str)
> > /* 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((CHAR16 *)mesg);
> > PrintErr(L": ");
> >
> > - switch (ErrCode)
> > + if( (ErrIdx < ARRAY_SIZE(ErrCodeToStr)) && ErrCodeToStr[ErrIdx] )
> > + mesg = ErrCodeToStr[ErrIdx];
> > + else
> > {
> > - 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/include/xen/init.h b/xen/include/xen/init.h
> > index fd8b614..671ac81 100644
> > --- a/xen/include/xen/init.h
> > +++ b/xen/include/xen/init.h
> > @@ -11,6 +11,7 @@
> > #define __exit __text_section(".exit.text")
> > #define __initdata __section(".init.data")
> > #define __initconst __section(".init.rodata")
> > +#define __initconstrel __section(".init.rodata.rel")
> > #define __exitdata __used_section(".exit.data")
> > #define __initsetup __used_section(".init.setup")
> > #define __init_call(lvl) __used_section(".initcall" lvl ".init")
> > --
> > 2.1.4
>
>
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |