| Message ID | BLU436-SMTP137847CF4664A5D26694FDBF930@phx.gbl |
|---|---|
| State | Superseded |
| Delegated to: | Simon Glass |
| Headers | show |
Hi Simon, On Mon, Jul 6, 2015 at 4:31 PM, Bin Meng <bmeng.cn@gmail.com> wrote: > From: Jian Luo <jian.luo4@boschrexroth.de> > > PCI option rom may use different SS during its execution, so it is not > safe to assume esp pointed to the same location in the protected mode. > > Signed-off-by: Jian Luo <jian.luo4@boschrexroth.de> > Signed-off-by: Bin Meng <bmeng.cn@gmail.com> > > --- > > Changes in v2: > - Add comments for the changes in the assembly codes > > arch/x86/lib/bios_asm.S | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/arch/x86/lib/bios_asm.S b/arch/x86/lib/bios_asm.S > index 4faa70e..e559228 100644 > --- a/arch/x86/lib/bios_asm.S > +++ b/arch/x86/lib/bios_asm.S > @@ -246,6 +246,9 @@ __interrupt_handler_16bit = PTR_TO_REAL_MODE(.) > push %fs > push %gs > > + /* Save real mode SS */ > + movw %ss, %cs:__realmode_ss > + > /* Clear DF to not break ABI assumptions */ > cld > > @@ -258,12 +261,29 @@ __interrupt_handler_16bit = PTR_TO_REAL_MODE(.) > > enter_protected_mode > > + /* > + * Now we are in protect mode. We need compute the right ESP based on > + * saved real mode SS otherwise interrupt_handler() won't get correct > + * parameters from the stack. > + */ > + movzwl %cs:__realmode_ss, %ecx > + shll $4, %ecx > + addl %ecx, %esp > + > /* Call the C interrupt handler */ > movl $interrupt_handler, %eax > call *%eax > > + /* Restore read mode ESP based on saved SS */ > + movzwl %cs:__realmode_ss, %ecx > + shll $4, %ecx > + subl %ecx, %esp > + > enter_real_mode > > + /* Restore real mode SS */ > + movw %cs:__realmode_ss, %ss > + > /* > * Restore all registers, including those manipulated by the C > * handler > @@ -276,6 +296,9 @@ __interrupt_handler_16bit = PTR_TO_REAL_MODE(.) > popal > iret > > +__realmode_ss = PTR_TO_REAL_MODE(.) > + .word 0 > + > .globl asm_realmode_code_size > asm_realmode_code_size: > .long . - asm_realmode_code > -- Sorry I have to respin this patch. Please check the new one here: http://patchwork.ozlabs.org/patch/491496/ Regards, Bin
diff --git a/arch/x86/lib/bios_asm.S b/arch/x86/lib/bios_asm.S index 4faa70e..e559228 100644 --- a/arch/x86/lib/bios_asm.S +++ b/arch/x86/lib/bios_asm.S @@ -246,6 +246,9 @@ __interrupt_handler_16bit = PTR_TO_REAL_MODE(.) push %fs push %gs + /* Save real mode SS */ + movw %ss, %cs:__realmode_ss + /* Clear DF to not break ABI assumptions */ cld @@ -258,12 +261,29 @@ __interrupt_handler_16bit = PTR_TO_REAL_MODE(.) enter_protected_mode + /* + * Now we are in protect mode. We need compute the right ESP based on + * saved real mode SS otherwise interrupt_handler() won't get correct + * parameters from the stack. + */ + movzwl %cs:__realmode_ss, %ecx + shll $4, %ecx + addl %ecx, %esp + /* Call the C interrupt handler */ movl $interrupt_handler, %eax call *%eax + /* Restore read mode ESP based on saved SS */ + movzwl %cs:__realmode_ss, %ecx + shll $4, %ecx + subl %ecx, %esp + enter_real_mode + /* Restore real mode SS */ + movw %cs:__realmode_ss, %ss + /* * Restore all registers, including those manipulated by the C * handler @@ -276,6 +296,9 @@ __interrupt_handler_16bit = PTR_TO_REAL_MODE(.) popal iret +__realmode_ss = PTR_TO_REAL_MODE(.) + .word 0 + .globl asm_realmode_code_size asm_realmode_code_size: .long . - asm_realmode_code