Re: [PATCH 1/2] LoongArch: Initialise unused Direct Map Windows

Hi, Jiaxun,

On Fri, Jun 14, 2024 at 12:41 AM Jiaxun Yang jiaxun.yang@flygoat.com wrote:

DMW 2 & 3 are unused by kernel, however firmware may leave garbage in them and interfere kernel's address mapping.

Clear them as necessary.

I think the current status is as expected, we don't want kernel access to non-8000 and non-9000 addresses. And low-end chips may have only two DMWs.

Huacai

Huacai

Cc: stable@vger.kernel.org Signed-off-by: Jiaxun Yang jiaxun.yang@flygoat.com

---

arch/loongarch/include/asm/loongarch.h | 4 ++++ arch/loongarch/include/asm/stackframe.h | 11 +++++++++++ arch/loongarch/kernel/head.S | 12 ++---------- arch/loongarch/power/suspend_asm.S | 6 +----- drivers/firmware/efi/libstub/loongarch.c | 2 ++ 5 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h index eb09adda54b7..3720096efcf9 100644 --- a/arch/loongarch/include/asm/loongarch.h +++ b/arch/loongarch/include/asm/loongarch.h @@ -889,6 +889,10 @@ #define CSR_DMW1_BASE (CSR_DMW1_VSEG << DMW_PABITS) #define CSR_DMW1_INIT (CSR_DMW1_BASE | CSR_DMW1_MAT | CSR_DMW1_PLV0)

+/* Direct Map window 2/3 - unused */ +#define CSR_DMW2_INIT 0 +#define CSR_DMW3_INIT 0

/* Performance Counter registers */ #define LOONGARCH_CSR_PERFCTRL0 0x200 /* 32 perf event 0 config */ #define LOONGARCH_CSR_PERFCNTR0 0x201 /* 64 perf event 0 count value */ diff --git a/arch/loongarch/include/asm/stackframe.h b/arch/loongarch/include/asm/stackframe.h index d9eafd3ee3d1..10c5dcf56bc7 100644 --- a/arch/loongarch/include/asm/stackframe.h +++ b/arch/loongarch/include/asm/stackframe.h @@ -38,6 +38,17 @@ cfi_restore \reg \offset \docfi .endm

•   .macro SETUP_DMWS temp1
  

•   li.d    \temp1, CSR_DMW0_INIT
  

•   csrwr   \temp1, LOONGARCH_CSR_DMWIN0
  

•   li.d    \temp1, CSR_DMW1_INIT
  

•   csrwr   \temp1, LOONGARCH_CSR_DMWIN1
  

•   li.d    \temp1, CSR_DMW2_INIT
  

•   csrwr   \temp1, LOONGARCH_CSR_DMWIN2
  

•   li.d    \temp1, CSR_DMW3_INIT
  

•   csrwr   \temp1, LOONGARCH_CSR_DMWIN3
  

•   .endm
  

/* Jump to the runtime virtual address. */ .macro JUMP_VIRT_ADDR temp1 temp2 li.d \temp1, CACHE_BASE diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S index 4677ea8fa8e9..1a71fc09bfd6 100644 --- a/arch/loongarch/kernel/head.S +++ b/arch/loongarch/kernel/head.S @@ -44,11 +44,7 @@ SYM_DATA(kernel_fsize, .long _kernel_fsize); SYM_CODE_START(kernel_entry) # kernel entry point

    /* Config direct window and set PG */

•   li.d            t0, CSR_DMW0_INIT       # UC, PLV0, 0x8000 xxxx xxxx xxxx
  

•   csrwr           t0, LOONGARCH_CSR_DMWIN0
  

•   li.d            t0, CSR_DMW1_INIT       # CA, PLV0, 0x9000 xxxx xxxx xxxx
  

•   csrwr           t0, LOONGARCH_CSR_DMWIN1
  

•   SETUP_DMWS      t0
    JUMP_VIRT_ADDR  t0, t1
  
    /* Enable PG */
  

@@ -124,11 +120,7 @@ SYM_CODE_END(kernel_entry)

• function after setting up the stack and tp registers.

*/ SYM_CODE_START(smpboot_entry)

•   li.d            t0, CSR_DMW0_INIT       # UC, PLV0
  

•   csrwr           t0, LOONGARCH_CSR_DMWIN0
  

•   li.d            t0, CSR_DMW1_INIT       # CA, PLV0
  

•   csrwr           t0, LOONGARCH_CSR_DMWIN1
  

•   SETUP_DMWS      t0
    JUMP_VIRT_ADDR  t0, t1
  
  

#ifdef CONFIG_PAGE_SIZE_4KB diff --git a/arch/loongarch/power/suspend_asm.S b/arch/loongarch/power/suspend_asm.S index e2fc3b4e31f0..6fdd74eb219b 100644 --- a/arch/loongarch/power/suspend_asm.S +++ b/arch/loongarch/power/suspend_asm.S @@ -73,11 +73,7 @@ SYM_FUNC_START(loongarch_suspend_enter) * Reload all of the registers and return. */ SYM_INNER_LABEL(loongarch_wakeup_start, SYM_L_GLOBAL)

•   li.d            t0, CSR_DMW0_INIT       # UC, PLV0
  

•   csrwr           t0, LOONGARCH_CSR_DMWIN0
  

•   li.d            t0, CSR_DMW1_INIT       # CA, PLV0
  

•   csrwr           t0, LOONGARCH_CSR_DMWIN1
  

•   SETUP_DMWS      t0
    JUMP_VIRT_ADDR  t0, t1
  
    /* Enable PG */
  

diff --git a/drivers/firmware/efi/libstub/loongarch.c b/drivers/firmware/efi/libstub/loongarch.c index d0ef93551c44..3782d0a187d1 100644 --- a/drivers/firmware/efi/libstub/loongarch.c +++ b/drivers/firmware/efi/libstub/loongarch.c @@ -74,6 +74,8 @@ efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image, /* Config Direct Mapping */ csr_write64(CSR_DMW0_INIT, LOONGARCH_CSR_DMWIN0); csr_write64(CSR_DMW1_INIT, LOONGARCH_CSR_DMWIN1);

•   csr_write64(CSR_DMW2_INIT, LOONGARCH_CSR_DMWIN2);
  

•   csr_write64(CSR_DMW3_INIT, LOONGARCH_CSR_DMWIN3);
  
    real_kernel_entry = (void *)kernel_entry_address(kernel_addr, image);
  
  
  

-- 2.43.0