| Message ID | 1438356724-6561-19-git-send-email-sjg@chromium.org |
|---|---|
| State | Accepted |
| Delegated to: | Simon Glass |
| Headers | show |
Hi Simon, On Fri, Jul 31, 2015 at 11:31 PM, Simon Glass <sjg@chromium.org> wrote: > On x86 the global_data pointer is provided through a somewhat-bizarre and > x86-specific mechanism: the F segment register is set to a pointer to the > start of global_data, so that accesses can use this build-in register. > > When running as an EFI payload we don't want to mess with the Global Nits: running as an EFI application > Descriptor Table (GDT) and there is little advantage (in terms of code size) > to doing so. > > Allow global_data to be a simple variable in this case. > > Signed-off-by: Simon Glass <sjg@chromium.org> > --- Reviewed-by: Bin Meng <bmeng.cn@gmail.com> > > Changes in v2: > - Move this patch to before the EFI start-up code patch > - Refer to FS as F segment register instead of frame segment register > - Rename CONFIG_ARCH_EFI to CONFIG_EFI_APP > > arch/x86/include/asm/global_data.h | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h > index 3db9a4c..80ebe3e 100644 > --- a/arch/x86/include/asm/global_data.h > +++ b/arch/x86/include/asm/global_data.h > @@ -76,6 +76,12 @@ struct arch_global_data { > #include <asm-generic/global_data.h> > > #ifndef __ASSEMBLY__ > +# ifdef CONFIG_EFI_APP > + > +#define gd global_data_ptr > + > +#define DECLARE_GLOBAL_DATA_PTR extern struct global_data *global_data_ptr > +# else > static inline __attribute__((no_instrument_function)) gd_t *get_fs_gd_ptr(void) > { > gd_t *gd_ptr; > @@ -88,6 +94,7 @@ static inline __attribute__((no_instrument_function)) gd_t *get_fs_gd_ptr(void) > #define gd get_fs_gd_ptr() > > #define DECLARE_GLOBAL_DATA_PTR > +# endif > > #endif > > -- Regards, Bin
On 2 August 2015 at 08:32, Bin Meng <bmeng.cn@gmail.com> wrote: > Hi Simon, > > On Fri, Jul 31, 2015 at 11:31 PM, Simon Glass <sjg@chromium.org> wrote: >> On x86 the global_data pointer is provided through a somewhat-bizarre and >> x86-specific mechanism: the F segment register is set to a pointer to the >> start of global_data, so that accesses can use this build-in register. >> >> When running as an EFI payload we don't want to mess with the Global > > Nits: running as an EFI application > >> Descriptor Table (GDT) and there is little advantage (in terms of code size) >> to doing so. >> >> Allow global_data to be a simple variable in this case. >> >> Signed-off-by: Simon Glass <sjg@chromium.org> >> --- > > Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Applied to u-boot-x86. > >> >> Changes in v2: >> - Move this patch to before the EFI start-up code patch >> - Refer to FS as F segment register instead of frame segment register >> - Rename CONFIG_ARCH_EFI to CONFIG_EFI_APP >> >> arch/x86/include/asm/global_data.h | 7 +++++++ >> 1 file changed, 7 insertions(+)
diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h index 3db9a4c..80ebe3e 100644 --- a/arch/x86/include/asm/global_data.h +++ b/arch/x86/include/asm/global_data.h @@ -76,6 +76,12 @@ struct arch_global_data { #include <asm-generic/global_data.h> #ifndef __ASSEMBLY__ +# ifdef CONFIG_EFI_APP + +#define gd global_data_ptr + +#define DECLARE_GLOBAL_DATA_PTR extern struct global_data *global_data_ptr +# else static inline __attribute__((no_instrument_function)) gd_t *get_fs_gd_ptr(void) { gd_t *gd_ptr; @@ -88,6 +94,7 @@ static inline __attribute__((no_instrument_function)) gd_t *get_fs_gd_ptr(void) #define gd get_fs_gd_ptr() #define DECLARE_GLOBAL_DATA_PTR +# endif #endif
On x86 the global_data pointer is provided through a somewhat-bizarre and x86-specific mechanism: the F segment register is set to a pointer to the start of global_data, so that accesses can use this build-in register. When running as an EFI payload we don't want to mess with the Global Descriptor Table (GDT) and there is little advantage (in terms of code size) to doing so. Allow global_data to be a simple variable in this case. Signed-off-by: Simon Glass <sjg@chromium.org> --- Changes in v2: - Move this patch to before the EFI start-up code patch - Refer to FS as F segment register instead of frame segment register - Rename CONFIG_ARCH_EFI to CONFIG_EFI_APP arch/x86/include/asm/global_data.h | 7 +++++++ 1 file changed, 7 insertions(+)