Re: [PATCH v3 1/3] riscv: Factorize xip and !xip kernel address conversion macros
From: Alex Ghiti
Date: Thu Jun 03 2021 - 11:06:50 EST
Le 3/06/2021 à 15:53, Jisheng Zhang a écrit :
On Thu, 3 Jun 2021 18:46:47 +0530
Anup Patel <anup@xxxxxxxxxxxxxx> wrote:
On Thu, Jun 3, 2021 at 6:27 PM Alex Ghiti <alex@xxxxxxxx> wrote:
Hi Jisheng,
Hi,
Le 3/06/2021 à 14:27, Jisheng Zhang a écrit :
On Thu, 3 Jun 2021 10:27:47 +0200
Alexandre Ghiti <alex@xxxxxxxx> wrote:
To simplify the kernel address conversion code, make the same definition of
kernel_mapping_pa_to_va and kernel_mapping_va_to_pa compatible for both xip
and !xip kernel by defining XIP_OFFSET to 0 in !xip kernel.
Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
---
arch/riscv/include/asm/page.h | 14 +++-----------
arch/riscv/include/asm/pgtable.h | 2 ++
2 files changed, 5 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index 6a7761c86ec2..6e004d8fda4d 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -93,9 +93,7 @@ extern unsigned long va_pa_offset;
#ifdef CONFIG_64BIT
extern unsigned long va_kernel_pa_offset;
#endif
-#ifdef CONFIG_XIP_KERNEL
extern unsigned long va_kernel_xip_pa_offset;
-#endif
extern unsigned long pfn_base;
#define ARCH_PFN_OFFSET (pfn_base)
#else
@@ -103,6 +101,7 @@ extern unsigned long pfn_base;
#ifdef CONFIG_64BIT
#define va_kernel_pa_offset 0
#endif
+#define va_kernel_xip_pa_offset 0
#define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT)
#endif /* CONFIG_MMU */
@@ -110,29 +109,22 @@ extern unsigned long kernel_virt_addr;
#ifdef CONFIG_64BIT
#define linear_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_pa_offset))
-#ifdef CONFIG_XIP_KERNEL
#define kernel_mapping_pa_to_va(y) ({ \
unsigned long _y = y; \
(_y >= CONFIG_PHYS_RAM_BASE) ?
This CONFIG_PHYS_RAM_BASE is only available for XIP, could result in a
compiler error for !XIP?
You're right, I have this patch in my branch and forgot to squash it
I'm also concerned with the unecessary overhead of kernel_mapping_pa_to_va()
for !XIP case, there's a "if" condition branch, and extra symbol: va_kernel_xip_pa_offset
I understand your concerns even if I don't find that the overhead is
that important here, I prefer the readability improvement. I can always
For readability, we still can avoid introducing va_kernel_xip_pa_offset
symbol by simply define va_kernel_xip_pa_offset as 0 if XIP as you did
for XIP_OFFSET
PS: this may need a preparation patch:
http://lists.infradead.org/pipermail/linux-riscv/2021-June/006802.html
IIUC, that won't improve readability, just avoid to allocate
va_kernel_xip_pa_offset in !XIP kernel right?
add unlikely/likely builtin to improve things or completely remove this
patch if others agree with you.
I would also prefer readable code for long-term maintainability. Currently,
the nested "#ifdefs" are increasing causing developers to easily break
untested combinations.
Regards,
Anup
Thanks,
Alex
(void *)((unsigned long)(_y) + va_kernel_pa_offset + XIP_OFFSET) : \
(void *)((unsigned long)(_y) + va_kernel_xip_pa_offset); \
})
-#else
-#define kernel_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_kernel_pa_offset))
-#endif
#define __pa_to_va_nodebug(x) linear_mapping_pa_to_va(x)
#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset)
-#ifdef CONFIG_XIP_KERNEL
#define kernel_mapping_va_to_pa(y) ({ \
unsigned long _y = y; \
(_y < kernel_virt_addr + XIP_OFFSET) ? \
((unsigned long)(_y) - va_kernel_xip_pa_offset) : \
((unsigned long)(_y) - va_kernel_pa_offset - XIP_OFFSET); \
})
Similar as kernel_mapping_pa_to_va(), an overhead of "if" condition branch
for !XIP and extra va_kernel_xip_pa_offset symbol.
-#else
-#define kernel_mapping_va_to_pa(x) ((unsigned long)(x) - va_kernel_pa_offset)
-#endif
+
#define __va_to_pa_nodebug(x) ({ \
unsigned long _x = x; \
(_x < kernel_virt_addr) ? \
@@ -141,7 +133,7 @@ extern unsigned long kernel_virt_addr;
#else
#define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset))
#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset)
-#endif
+#endif /* CONFIG_64BIT */
#ifdef CONFIG_DEBUG_VIRTUAL
extern phys_addr_t __virt_to_phys(unsigned long x);
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index bde8ce3bfe7c..d98e931a31e5 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -77,6 +77,8 @@
#ifdef CONFIG_XIP_KERNEL
#define XIP_OFFSET SZ_8M
+#else
+#define XIP_OFFSET 0
#endif
#ifndef __ASSEMBLY__
_______________________________________________
linux-riscv mailing list
linux-riscv@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/linux-riscv
_______________________________________________
linux-riscv mailing list
linux-riscv@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/linux-riscv