[U-Boot] [PATCH 1/1] x86: put global data pointer into the .text section
On x86_64 the field global_data_ptr is assigned before relocation. As global data sections (.data and .bss) overlap with the relocation sections (.rela) this destroys the relocation table and leads to spurious errors.
By moving the field to the .text section it will not overlap any relocation section anymore.
Fixes: a160092a610f ("x86: Support global_data on x86_64") Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- arch/x86/cpu/x86_64/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/cpu/x86_64/cpu.c b/arch/x86/cpu/x86_64/cpu.c index 18b3e94e12..676a789524 100644 --- a/arch/x86/cpu/x86_64/cpu.c +++ b/arch/x86/cpu/x86_64/cpu.c @@ -8,7 +8,7 @@ #include <debug_uart.h>
/* Global declaration of gd */ -struct global_data *global_data_ptr; +struct global_data *global_data_ptr __attribute__((section(".text")));
void arch_setup_gd(gd_t *new_gd) {
Hi Heinrich,
On Sat, Oct 13, 2018 at 9:07 AM Heinrich Schuchardt xypron.glpk@gmx.de wrote:
On x86_64 the field global_data_ptr is assigned before relocation. As global data sections (.data and .bss) overlap with the relocation sections
Good catch! But I think the x86_64 global data is in the .bss, not .data. .data is not overlapped with the .rela section.
(.rela) this destroys the relocation table and leads to spurious errors.
By moving the field to the .text section it will not overlap any relocation section anymore.
Fixes: a160092a610f ("x86: Support global_data on x86_64") Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de
arch/x86/cpu/x86_64/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Regards, Bin
On Sat, Oct 13, 2018 at 12:57 PM Bin Meng bmeng.cn@gmail.com wrote:
Hi Heinrich,
On Sat, Oct 13, 2018 at 9:07 AM Heinrich Schuchardt xypron.glpk@gmx.de wrote:
On x86_64 the field global_data_ptr is assigned before relocation. As global data sections (.data and .bss) overlap with the relocation sections
Good catch! But I think the x86_64 global data is in the .bss, not .data. .data is not overlapped with the .rela section.
(.rela) this destroys the relocation table and leads to spurious errors.
By moving the field to the .text section it will not overlap any relocation section anymore.
Looks putting global data to .text will cause the following error:
{standard input}: Assembler messages: {standard input}:6: Warning: ignoring changed section attributes for .text
I am not sure how to suppress it.
Fixes: a160092a610f ("x86: Support global_data on x86_64") Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de
Regards, Bin
Hi Heinrich,
On Sat, Oct 13, 2018 at 12:57 PM Bin Meng bmeng.cn@gmail.com wrote:
Hi Heinrich,
On Sat, Oct 13, 2018 at 9:07 AM Heinrich Schuchardt xypron.glpk@gmx.de wrote:
On x86_64 the field global_data_ptr is assigned before relocation. As global data sections (.data and .bss) overlap with the relocation sections
Good catch! But I think the x86_64 global data is in the .bss, not .data. .data is not overlapped with the .rela section.
(.rela) this destroys the relocation table and leads to spurious errors.
By moving the field to the .text section it will not overlap any relocation section anymore.
It turns out putting this field to the .data section will fix this issue, without causing any compiler warning.
diff --git a/arch/x86/cpu/x86_64/cpu.c b/arch/x86/cpu/x86_64/cpu.c index 676a789..2e602f3 100644 --- a/arch/x86/cpu/x86_64/cpu.c +++ b/arch/x86/cpu/x86_64/cpu.c @@ -8,7 +8,7 @@ #include <debug_uart.h>
/* Global declaration of gd */ -struct global_data *global_data_ptr __attribute__((section(".text"))); +struct global_data *global_data_ptr __attribute__((section(".data")));
Regards, Bin
participants (2)
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Bin Meng -
Heinrich Schuchardt