| Message ID | 20190722213958.5761-24-julien.grall@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen/arm: Rework head.S to make it more compliant with the Arm Arm | expand |
On Mon, 22 Jul 2019, Julien Grall wrote: > At the moment, the user should save r14/lr if it cares about it. > > Follow-up patches will introduce more use of putn in place where lr > should be preserved. > > Furthermore, any user of putn should also move the value to register r0 > if it was stored in a different register. > > For convenience, a new macro is introduced to print a given register. > The macro will take care for us to move the value to r0 and also > preserve lr. > > Lastly the new macro is used to replace all the callsite of putn. This > will simplify rework/review later on. > > Signed-off-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > Changes in v2: > - Patch added > --- > xen/arch/arm/arm32/head.S | 23 +++++++++++++++++++---- > 1 file changed, 19 insertions(+), 4 deletions(-) > > diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S > index 134c3dda92..bbcfdcd351 100644 > --- a/xen/arch/arm/arm32/head.S > +++ b/xen/arch/arm/arm32/head.S > @@ -79,8 +79,25 @@ > 98: .asciz _s ;\ > .align 2 ;\ > 99: > + > +/* > + * Macro to print the value of register \rb > + * > + * Clobbers r0 - r4 > + */ > +.macro print_reg rb > + mov r0, \rb > + mov r4, lr > + bl putn > + mov lr, r4 > +.endm > + > #else /* CONFIG_EARLY_PRINTK */ > #define PRINT(s) > + > +.macro print_reg rb > +.endm > + > #endif /* !CONFIG_EARLY_PRINTK */ > > .arm > @@ -159,8 +176,7 @@ GLOBAL(init_secondary) > #ifdef CONFIG_EARLY_PRINTK > mov_w r11, EARLY_UART_BASE_ADDRESS /* r11 := UART base address */ > PRINT("- CPU ") > - mov r0, r7 > - bl putn > + print_reg r7 > PRINT(" booting -\r\n") > #endif > > @@ -211,8 +227,7 @@ skip_bss: > bne 1f > mov r4, r0 > PRINT("- Missing processor info: ") > - mov r0, r4 > - bl putn > + print_reg r4 > PRINT(" -\r\n") > b fail > 1: > -- > 2.11.0 >
diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index 134c3dda92..bbcfdcd351 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -79,8 +79,25 @@ 98: .asciz _s ;\ .align 2 ;\ 99: + +/* + * Macro to print the value of register \rb + * + * Clobbers r0 - r4 + */ +.macro print_reg rb + mov r0, \rb + mov r4, lr + bl putn + mov lr, r4 +.endm + #else /* CONFIG_EARLY_PRINTK */ #define PRINT(s) + +.macro print_reg rb +.endm + #endif /* !CONFIG_EARLY_PRINTK */ .arm @@ -159,8 +176,7 @@ GLOBAL(init_secondary) #ifdef CONFIG_EARLY_PRINTK mov_w r11, EARLY_UART_BASE_ADDRESS /* r11 := UART base address */ PRINT("- CPU ") - mov r0, r7 - bl putn + print_reg r7 PRINT(" booting -\r\n") #endif @@ -211,8 +227,7 @@ skip_bss: bne 1f mov r4, r0 PRINT("- Missing processor info: ") - mov r0, r4 - bl putn + print_reg r4 PRINT(" -\r\n") b fail 1:
At the moment, the user should save r14/lr if it cares about it. Follow-up patches will introduce more use of putn in place where lr should be preserved. Furthermore, any user of putn should also move the value to register r0 if it was stored in a different register. For convenience, a new macro is introduced to print a given register. The macro will take care for us to move the value to r0 and also preserve lr. Lastly the new macro is used to replace all the callsite of putn. This will simplify rework/review later on. Signed-off-by: Julien Grall <julien.grall@arm.com> --- Changes in v2: - Patch added --- xen/arch/arm/arm32/head.S | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-)