| Message ID | 20231107110217.1827379-2-ayan.kumar.halder@amd.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen/arm: Split MMU code as the prepration of MPU work form Arm32 | expand |
Hi Ayan, On 07/11/2023 12:02, Ayan Kumar Halder wrote: > All the MMU related functionality have been clubbed together in > enable_boot_cpu_mm() for booting primary cpu and enable_secondary_cpu_mm() for > booting secondary cpus. > This is done in preparation for moving the code related to MMU in MMU specific > file and in order to support non MMU cpus in future. > > This is based on d2f8df5b3ede ("xen/arm64: head.S: Introduce enable_{boot,secondary}_cpu_mm()"). > > Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com> > Reviewed-by: Michal Orzel <michal.orzel@amd.com> > Acked-by: Julien Grall <jgrall@amazon.com> > --- > > Changes from :- > > v1 - 1. Added a proper commit message. > 2. Some style and other fixes suggested in v1. > > v2 - 1. Updated the comment on top of enable_boot_cpu_mm() and > enable_secondary_cpu_mm() ie mentioned the input and output registers. > 2. Updated the comment inside enable_boot_cpu_mm(). > > xen/arch/arm/arm32/head.S | 102 ++++++++++++++++++++++++++++++-------- > 1 file changed, 80 insertions(+), 22 deletions(-) > > diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S > index 2d7e690bf5..2204ea6dce 100644 > --- a/xen/arch/arm/arm32/head.S > +++ b/xen/arch/arm/arm32/head.S > @@ -201,13 +201,11 @@ past_zImage: > > bl check_cpu_mode > bl cpu_init > - bl create_page_tables > > - /* Address in the runtime mapping to jump to after the MMU is enabled */ > mov_w lr, primary_switched > - b enable_mmu > + b enable_boot_cpu_mm > + > primary_switched: > - bl setup_fixmap > #ifdef CONFIG_EARLY_PRINTK > /* Use a virtual address to access the UART. */ > mov_w r11, EARLY_UART_VIRTUAL_ADDRESS > @@ -249,27 +247,11 @@ GLOBAL(init_secondary) > #endif > bl check_cpu_mode > bl cpu_init > - bl create_page_tables > > - /* Address in the runtime mapping to jump to after the MMU is enabled */ > mov_w lr, secondary_switched > - b enable_mmu > -secondary_switched: > - /* > - * Non-boot CPUs need to move on to the proper pagetables, which were > - * setup in prepare_secondary_mm. > - * > - * XXX: This is not compliant with the Arm Arm. > - */ > - mov_w r4, init_ttbr /* VA of HTTBR value stashed by CPU 0 */ > - ldrd r4, r5, [r4] /* Actual value */ > - dsb > - mcrr CP64(r4, r5, HTTBR) > - dsb > - isb > - flush_xen_tlb_local r0 > - pt_enforce_wxn r0 > + b enable_secondary_cpu_mm > > +secondary_switched: > #ifdef CONFIG_EARLY_PRINTK > /* Use a virtual address to access the UART. */ > mov_w r11, EARLY_UART_VIRTUAL_ADDRESS > @@ -692,6 +674,82 @@ ready_to_switch: > mov pc, lr > ENDPROC(switch_to_runtime_mapping) > > +/* > + * Enable mm (turn on the data cache and the MMU) for secondary CPUs. > + * The function will return to the virtual address provided in LR (e.g. the > + * runtime mapping). > + * > + * Inputs: > + * r9 : paddr(start) > + * r10: phys offset > + * lr : Virtual address to return to. > + * > + * Output: > + * r12: Was a temporary mapping created? > + * > + * Clobbers r0 - r6 > + */ > +enable_secondary_cpu_mm: > + mov r6, lr > + > + bl create_page_tables > + > + /* Address in the runtime mapping to jump to after the MMU is enabled */ > + mov_w lr, 1f > + b enable_mmu > +1: > + /* > + * Non-boot CPUs need to move on to the proper pagetables, which were > + * setup in prepare_secondary_mm. > + * > + * XXX: This is not compliant with the Arm Arm. > + */ > + mov_w r4, init_ttbr /* VA of HTTBR value stashed by CPU 0 */ > + ldrd r4, r5, [r4] /* Actual value */ > + dsb > + mcrr CP64(r4, r5, HTTBR) > + dsb > + isb > + flush_xen_tlb_local r0 > + pt_enforce_wxn r0 > + > + /* Return to the virtual address requested by the caller. */ > + mov pc, r6 > +ENDPROC(enable_secondary_cpu_mm) > + > +/* > + * Enable mm (turn on the data cache and the MMU) for the boot CPU. > + * The function will return to the virtual address provided in LR (e.g. the > + * runtime mapping). > + * > + * Inputs: > + * r9 : paddr(start) > + * r10: phys offset > + * lr : Virtual address to return to. > + * > + * Output: > + * r12: Was a temporary mapping created? > + * > + * Clobbers r0 - r6 > + */ > +enable_boot_cpu_mm: > + mov r6, lr > + > + bl create_page_tables > + > + /* Address in the runtime mapping to jump to after the MMU is enabled */ > + mov_w lr, 1f > + b enable_mmu > +1: > + /* > + * Prepare the fixmap. The function will return to the virtual address > + * requested by the caller. > + */ This comment should be above branch instruction and not here. ~Michal
diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index 2d7e690bf5..2204ea6dce 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -201,13 +201,11 @@ past_zImage: bl check_cpu_mode bl cpu_init - bl create_page_tables - /* Address in the runtime mapping to jump to after the MMU is enabled */ mov_w lr, primary_switched - b enable_mmu + b enable_boot_cpu_mm + primary_switched: - bl setup_fixmap #ifdef CONFIG_EARLY_PRINTK /* Use a virtual address to access the UART. */ mov_w r11, EARLY_UART_VIRTUAL_ADDRESS @@ -249,27 +247,11 @@ GLOBAL(init_secondary) #endif bl check_cpu_mode bl cpu_init - bl create_page_tables - /* Address in the runtime mapping to jump to after the MMU is enabled */ mov_w lr, secondary_switched - b enable_mmu -secondary_switched: - /* - * Non-boot CPUs need to move on to the proper pagetables, which were - * setup in prepare_secondary_mm. - * - * XXX: This is not compliant with the Arm Arm. - */ - mov_w r4, init_ttbr /* VA of HTTBR value stashed by CPU 0 */ - ldrd r4, r5, [r4] /* Actual value */ - dsb - mcrr CP64(r4, r5, HTTBR) - dsb - isb - flush_xen_tlb_local r0 - pt_enforce_wxn r0 + b enable_secondary_cpu_mm +secondary_switched: #ifdef CONFIG_EARLY_PRINTK /* Use a virtual address to access the UART. */ mov_w r11, EARLY_UART_VIRTUAL_ADDRESS @@ -692,6 +674,82 @@ ready_to_switch: mov pc, lr ENDPROC(switch_to_runtime_mapping) +/* + * Enable mm (turn on the data cache and the MMU) for secondary CPUs. + * The function will return to the virtual address provided in LR (e.g. the + * runtime mapping). + * + * Inputs: + * r9 : paddr(start) + * r10: phys offset + * lr : Virtual address to return to. + * + * Output: + * r12: Was a temporary mapping created? + * + * Clobbers r0 - r6 + */ +enable_secondary_cpu_mm: + mov r6, lr + + bl create_page_tables + + /* Address in the runtime mapping to jump to after the MMU is enabled */ + mov_w lr, 1f + b enable_mmu +1: + /* + * Non-boot CPUs need to move on to the proper pagetables, which were + * setup in prepare_secondary_mm. + * + * XXX: This is not compliant with the Arm Arm. + */ + mov_w r4, init_ttbr /* VA of HTTBR value stashed by CPU 0 */ + ldrd r4, r5, [r4] /* Actual value */ + dsb + mcrr CP64(r4, r5, HTTBR) + dsb + isb + flush_xen_tlb_local r0 + pt_enforce_wxn r0 + + /* Return to the virtual address requested by the caller. */ + mov pc, r6 +ENDPROC(enable_secondary_cpu_mm) + +/* + * Enable mm (turn on the data cache and the MMU) for the boot CPU. + * The function will return to the virtual address provided in LR (e.g. the + * runtime mapping). + * + * Inputs: + * r9 : paddr(start) + * r10: phys offset + * lr : Virtual address to return to. + * + * Output: + * r12: Was a temporary mapping created? + * + * Clobbers r0 - r6 + */ +enable_boot_cpu_mm: + mov r6, lr + + bl create_page_tables + + /* Address in the runtime mapping to jump to after the MMU is enabled */ + mov_w lr, 1f + b enable_mmu +1: + /* + * Prepare the fixmap. The function will return to the virtual address + * requested by the caller. + */ + mov lr, r6 + + b setup_fixmap +ENDPROC(enable_boot_cpu_mm) + /* * Remove the 1:1 map from the page-tables. It is not easy to keep track * where the 1:1 map was mapped, so we will look for the top-level entry
All the MMU related functionality have been clubbed together in enable_boot_cpu_mm() for booting primary cpu and enable_secondary_cpu_mm() for booting secondary cpus. This is done in preparation for moving the code related to MMU in MMU specific file and in order to support non MMU cpus in future. This is based on d2f8df5b3ede ("xen/arm64: head.S: Introduce enable_{boot,secondary}_cpu_mm()"). Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com> Reviewed-by: Michal Orzel <michal.orzel@amd.com> Acked-by: Julien Grall <jgrall@amazon.com> --- Changes from :- v1 - 1. Added a proper commit message. 2. Some style and other fixes suggested in v1. v2 - 1. Updated the comment on top of enable_boot_cpu_mm() and enable_secondary_cpu_mm() ie mentioned the input and output registers. 2. Updated the comment inside enable_boot_cpu_mm(). xen/arch/arm/arm32/head.S | 102 ++++++++++++++++++++++++++++++-------- 1 file changed, 80 insertions(+), 22 deletions(-)