diff mbox series

[1/2] microblaze: start.S: Factor out exception setup code to __setup_exceptions

Message ID 20200920165023.6227-1-ovidiu.panait@windriver.com
State Deferred
Delegated to: Tom Rini
Headers show
Series [1/2] microblaze: start.S: Factor out exception setup code to __setup_exceptions | expand

Commit Message

Ovidiu Panait Sept. 20, 2020, 4:50 p.m. UTC 
Currently, the exceptions setup code is duplicated in pre-relocation and
post-relocation init. Factor out this code to __setup_exceptions asm
routine to get rid of the duplication.

__setup_exceptions is called with a relocation offset parameter (r5)
which is set to zero for pre-reloc init and gd->reloc_off for post-reloc
exception setup.

Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
---

 arch/microblaze/cpu/start.S | 183 +++++++++++++++++-------------------
 1 file changed, 88 insertions(+), 95 deletions(-)

Comments

Michal Simek Sept. 23, 2020, 2:47 p.m. UTC | #1 
On 20. 09. 20 18:50, Ovidiu Panait wrote:
> Currently, the exceptions setup code is duplicated in pre-relocation and
> post-relocation init. Factor out this code to __setup_exceptions asm
> routine to get rid of the duplication.
> 
> __setup_exceptions is called with a relocation offset parameter (r5)
> which is set to zero for pre-reloc init and gd->reloc_off for post-reloc
> exception setup.
> 
> Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
> ---
> 
>  arch/microblaze/cpu/start.S | 183 +++++++++++++++++-------------------
>  1 file changed, 88 insertions(+), 95 deletions(-)
> 
> diff --git a/arch/microblaze/cpu/start.S b/arch/microblaze/cpu/start.S
> index cbec299b7d..f3be014317 100644
> --- a/arch/microblaze/cpu/start.S
> +++ b/arch/microblaze/cpu/start.S
> @@ -13,13 +13,6 @@
>  	.text
>  	.global _start
>  _start:
> -	/*
> -	 * reserve registers:
> -	 * r10: Stores little/big endian offset for vectors
> -	 * r2: Stores imm opcode
> -	 * r3: Stores brai opcode
> -	 */
> -
>  	mts	rmsr, r0	/* disable cache */
>  
>  	addi	r8, r0, __end
> @@ -38,6 +31,84 @@ _start:
>  	mts	rshr, r1
>  	addi	r1, r1, -4	/* Decrement SP to top of memory */
>  
> +	/* Setup vectors with pre-relocation symbols */
> +	or r5, r0, r0
> +	bralid r15, __setup_exceptions
> +	nop

Please align code with the rest which is tab between asm instruction and
arguments.


> +#endif /* CONFIG_SPL_BUILD */
> +
> +	/* Flush cache before enable cache */
> +	addik	r5, r0, 0
> +	addik	r6, r0, XILINX_DCACHE_BYTE_SIZE
> +	bralid r15, flush_cache
> +	nop
> +
> +	/* enable instruction and data cache */
> +	mfs	r12, rmsr
> +	ori	r12, r12, 0x1a0
> +	mts	rmsr, r12
> +
> +	/* TODO: Redo this code to call board_init_f_*() */
> +clear_bss:
> +	/* clear BSS segments */
> +	addi	r5, r0, __bss_start
> +	addi	r4, r0, __bss_end
> +	cmp	r6, r5, r4
> +	beqi	r6, 3f
> +2:
> +	swi     r0, r5, 0 /* write zero to loc */
> +	addi    r5, r5, 4 /* increment to next loc */
> +	cmp     r6, r5, r4 /* check if we have reach the end */
> +	bnei    r6, 2b
> +3:	/* jumping to board_init */
> +#ifdef CONFIG_DEBUG_UART
> +	bralid	r15, debug_uart_init
> +	nop
> +#endif
> +#ifndef CONFIG_SPL_BUILD
> +	or	r5, r0, r0	/* flags - empty */
> +	addi    r31, r0, _gd
> +#if CONFIG_VAL(SYS_MALLOC_F_LEN)
> +	addi	r6, r0, CONFIG_SYS_INIT_SP_OFFSET
> +	swi	r6, r31, GD_MALLOC_BASE
> +#endif
> +	brai	board_init_f
> +#else
> +	addi	r31, r0, _gd
> +#if CONFIG_VAL(SYS_MALLOC_F_LEN)
> +	addi	r6, r0, CONFIG_SPL_STACK_ADDR
> +	swi	r6, r31, GD_MALLOC_BASE
> +#endif
> +	brai	board_init_r
> +#endif
> +1:	bri	1b
> +
> + .section .bss
> +.align 4
> +_gd:
> +         .space  GENERATED_GBL_DATA_SIZE
> +
> +#ifndef CONFIG_SPL_BUILD
> +	.text
> +	.ent	__setup_exceptions
> +	.align	2
> +/*
> + * Set up reset, interrupt, user exception and hardware exception vectors.
> + *
> + * Parameters:
> + * r5 - relocation offset (zero when setting up vectors before
> + *      relocation, and gd->reloc_off when setting up vectors after
> + *      relocation)
> + *    - the relocation offset is added to the _exception_handler,
> + *      _interrupt_handler and _hw_exception_handler symbols to reflect the
> + *      post-relocation memory addresses
> + *
> + * Reserve registers:
> + * r10: Stores little/big endian offset for vectors
> + * r2: Stores imm opcode
> + * r3: Stores brai opcode

This is the biggest problem I have with this series. This function is
called from early code which is just the code below with return here
where certain registers are used and I expect this is working well.
But when this function is called from relocate code function these
registers can be used already and this function is not saving them.

I would rather see that regs saved to stack just for sure.

Thanks,
Michal
diff mbox series

Patch

diff --git a/arch/microblaze/cpu/start.S b/arch/microblaze/cpu/start.S
index cbec299b7d..f3be014317 100644
--- a/arch/microblaze/cpu/start.S
+++ b/arch/microblaze/cpu/start.S
@@ -13,13 +13,6 @@ 
 	.text
 	.global _start
 _start:
-	/*
-	 * reserve registers:
-	 * r10: Stores little/big endian offset for vectors
-	 * r2: Stores imm opcode
-	 * r3: Stores brai opcode
-	 */
-
 	mts	rmsr, r0	/* disable cache */
 
 	addi	r8, r0, __end
@@ -38,6 +31,84 @@  _start:
 	mts	rshr, r1
 	addi	r1, r1, -4	/* Decrement SP to top of memory */
 
+	/* Setup vectors with pre-relocation symbols */
+	or r5, r0, r0
+	bralid r15, __setup_exceptions
+	nop
+#endif /* CONFIG_SPL_BUILD */
+
+	/* Flush cache before enable cache */
+	addik	r5, r0, 0
+	addik	r6, r0, XILINX_DCACHE_BYTE_SIZE
+	bralid r15, flush_cache
+	nop
+
+	/* enable instruction and data cache */
+	mfs	r12, rmsr
+	ori	r12, r12, 0x1a0
+	mts	rmsr, r12
+
+	/* TODO: Redo this code to call board_init_f_*() */
+clear_bss:
+	/* clear BSS segments */
+	addi	r5, r0, __bss_start
+	addi	r4, r0, __bss_end
+	cmp	r6, r5, r4
+	beqi	r6, 3f
+2:
+	swi     r0, r5, 0 /* write zero to loc */
+	addi    r5, r5, 4 /* increment to next loc */
+	cmp     r6, r5, r4 /* check if we have reach the end */
+	bnei    r6, 2b
+3:	/* jumping to board_init */
+#ifdef CONFIG_DEBUG_UART
+	bralid	r15, debug_uart_init
+	nop
+#endif
+#ifndef CONFIG_SPL_BUILD
+	or	r5, r0, r0	/* flags - empty */
+	addi    r31, r0, _gd
+#if CONFIG_VAL(SYS_MALLOC_F_LEN)
+	addi	r6, r0, CONFIG_SYS_INIT_SP_OFFSET
+	swi	r6, r31, GD_MALLOC_BASE
+#endif
+	brai	board_init_f
+#else
+	addi	r31, r0, _gd
+#if CONFIG_VAL(SYS_MALLOC_F_LEN)
+	addi	r6, r0, CONFIG_SPL_STACK_ADDR
+	swi	r6, r31, GD_MALLOC_BASE
+#endif
+	brai	board_init_r
+#endif
+1:	bri	1b
+
+ .section .bss
+.align 4
+_gd:
+         .space  GENERATED_GBL_DATA_SIZE
+
+#ifndef CONFIG_SPL_BUILD
+	.text
+	.ent	__setup_exceptions
+	.align	2
+/*
+ * Set up reset, interrupt, user exception and hardware exception vectors.
+ *
+ * Parameters:
+ * r5 - relocation offset (zero when setting up vectors before
+ *      relocation, and gd->reloc_off when setting up vectors after
+ *      relocation)
+ *    - the relocation offset is added to the _exception_handler,
+ *      _interrupt_handler and _hw_exception_handler symbols to reflect the
+ *      post-relocation memory addresses
+ *
+ * Reserve registers:
+ * r10: Stores little/big endian offset for vectors
+ * r2: Stores imm opcode
+ * r3: Stores brai opcode
+ */
+__setup_exceptions:
 	/* Find-out if u-boot is running on BIG/LITTLE endian platform
 	 * There are some steps which is necessary to keep in mind:
 	 * 1. Setup offset value to r6
@@ -76,7 +147,7 @@  _start:
 	swi	r2, r0, 0x8	/* user vector exception - imm opcode */
 	swi	r3, r0, 0xC	/* user vector exception - brai opcode */
 
-	addik	r6, r0, _exception_handler
+	addik	r6, r5, _exception_handler
 	sw	r6, r1, r0
 	/*
 	 * BIG ENDIAN memory map for user exception
@@ -109,7 +180,7 @@  _start:
 	swi	r2, r0, 0x10	/* interrupt - imm opcode */
 	swi	r3, r0, 0x14	/* interrupt - brai opcode */
 
-	addik	r6, r0, _interrupt_handler
+	addik	r6, r5, _interrupt_handler
 	sw	r6, r1, r0
 	lhu	r7, r1, r10
 	rsubi	r8, r10, 0x12
@@ -121,67 +192,18 @@  _start:
 	swi	r2, r0, 0x20	/* hardware exception - imm opcode */
 	swi	r3, r0, 0x24	/* hardware exception - brai opcode */
 
-	addik	r6, r0, _hw_exception_handler
+	addik	r6, r5, _hw_exception_handler
 	sw	r6, r1, r0
 	lhu	r7, r1, r10
 	rsubi	r8, r10, 0x22
 	sh	r7, r0, r8
 	rsubi	r8, r10, 0x26
 	sh	r6, r0, r8
-#endif /* CONFIG_SPL_BUILD */
-
-	/* Flush cache before enable cache */
-	addik	r5, r0, 0
-	addik	r6, r0, XILINX_DCACHE_BYTE_SIZE
-	bralid r15, flush_cache
-	nop
-
-	/* enable instruction and data cache */
-	mfs	r12, rmsr
-	ori	r12, r12, 0x1a0
-	mts	rmsr, r12
 
-	/* TODO: Redo this code to call board_init_f_*() */
-clear_bss:
-	/* clear BSS segments */
-	addi	r5, r0, __bss_start
-	addi	r4, r0, __bss_end
-	cmp	r6, r5, r4
-	beqi	r6, 3f
-2:
-	swi     r0, r5, 0 /* write zero to loc */
-	addi    r5, r5, 4 /* increment to next loc */
-	cmp     r6, r5, r4 /* check if we have reach the end */
-	bnei    r6, 2b
-3:	/* jumping to board_init */
-#ifdef CONFIG_DEBUG_UART
-	bralid	r15, debug_uart_init
-	nop
-#endif
-#ifndef CONFIG_SPL_BUILD
-	or	r5, r0, r0	/* flags - empty */
-	addi    r31, r0, _gd
-#if CONFIG_VAL(SYS_MALLOC_F_LEN)
-	addi	r6, r0, CONFIG_SYS_INIT_SP_OFFSET
-	swi	r6, r31, GD_MALLOC_BASE
-#endif
-	brai	board_init_f
-#else
-	addi	r31, r0, _gd
-#if CONFIG_VAL(SYS_MALLOC_F_LEN)
-	addi	r6, r0, CONFIG_SPL_STACK_ADDR
-	swi	r6, r31, GD_MALLOC_BASE
-#endif
-	brai	board_init_r
-#endif
-1:	bri	1b
-
- .section .bss
-.align 4
-_gd:
-         .space  GENERATED_GBL_DATA_SIZE
+	rtsd	r15, 8
+	or	r0, r0, r0
+	.end	__setup_exceptions
 
-#ifndef CONFIG_SPL_BUILD
 /*
  * Read 16bit little endian
  */
@@ -249,39 +271,10 @@  relocate_code:
 	addi	r24, r0, CONFIG_SYS_TEXT_BASE /* Get reloc offset */
 	rsub	r23, r24, r23 /* keep - this is already here gd->reloc_off */
 
-	addik	r6, r0, 0x2 /* BIG/LITTLE endian offset */
-	lwi	r7, r0, 0x28
-	swi	r6, r0, 0x28 /* used first unused MB vector */
-	lbui	r10, r0, 0x28 /* used first unused MB vector */
-	swi	r7, r0, 0x28
-
-#ifdef CONFIG_SYS_USR_EXCEP
-	addik	r6, r0, _exception_handler
-	addk	r6, r6, r23 /* add offset */
-	sw	r6, r1, r0
-	lhu	r7, r1, r10
-	rsubi	r8, r10, 0xa
-	sh	r7, r0, r8
-	rsubi	r8, r10, 0xe
-	sh	r6, r0, r8
-#endif
-	addik	r6, r0, _hw_exception_handler
-	addk	r6, r6, r23 /* add offset */
-	sw	r6, r1, r0
-	lhu	r7, r1, r10
-	rsubi	r8, r10, 0x22
-	sh	r7, r0, r8
-	rsubi	r8, r10, 0x26
-	sh	r6, r0, r8
-
-	addik	r6, r0, _interrupt_handler
-	addk	r6, r6, r23 /* add offset */
-	sw	r6, r1, r0
-	lhu	r7, r1, r10
-	rsubi	r8, r10, 0x12
-	sh	r7, r0, r8
-	rsubi	r8, r10, 0x16
-	sh	r6, r0, r8
+	/* Setup vectors with post-relocation symbols */
+	add r5, r0, r23 /* load gd->reloc_off to r5 */
+	bralid r15, __setup_exceptions
+	nop
 
 	/* Check if GOT exist */
 	addik	r21, r23, _got_start