Re: [PATCH] RISC-V: Always define XIP_FIXUP

From: Alex Ghiti
Date: Sun May 02 2021 - 04:39:30 EST


Hi Palmer,

Le 4/29/21 à 12:43 AM, Palmer Dabbelt a écrit :
On Wed, 28 Apr 2021 01:25:55 PDT (-0700), alex@xxxxxxxx wrote:
Le 4/27/21 à 11:34 PM, Palmer Dabbelt a écrit :
From: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>

XIP depends on MMU, but XIP_FIXUP is defined throughout the kernel in
order to avoid excessive ifdefs.  This just makes sure to always define
XIP_FIXIP, which will fix MMU=n builds.

A small typo here.

Actually two: "defined" should have been "used".  Both are fixed.



Fixes: 44c922572952 ("RISC-V: enable XIP")
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
---
  arch/riscv/include/asm/pgtable.h | 24 ++++++++++++------------
  1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 2f1384e14e31..fd749351f432 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -73,18 +73,6 @@
  #endif
  #define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)

-#ifdef CONFIG_XIP_KERNEL
-#define XIP_OFFSET        SZ_8M
-#define XIP_FIXUP(addr) ({                            \
-    uintptr_t __a = (uintptr_t)(addr);                    \
-    (__a >= CONFIG_XIP_PHYS_ADDR && __a < CONFIG_XIP_PHYS_ADDR + SZ_16M) ?    \
-        __a - CONFIG_XIP_PHYS_ADDR + CONFIG_PHYS_RAM_BASE - XIP_OFFSET :\
-        __a;                                \
-    })
-#else
-#define XIP_FIXUP(addr)        (addr)
-#endif /* CONFIG_XIP_KERNEL */
-
  #endif

  #ifndef __ASSEMBLY__
@@ -101,6 +89,18 @@
  #include <asm/pgtable-32.h>
  #endif /* CONFIG_64BIT */

+#ifdef CONFIG_XIP_KERNEL
+#define XIP_OFFSET        SZ_8M


XIP_OFFSET is used in head.S and then this breaks XIP_KERNEL. XIP_OFFSET
must live outside the ifndef __ASSEMBLY__.

Thanks, I hadn't even seen XIP_OFFSET.  This is fixed in the v2.

Do you have an XIP config that will run on QEMU, and a way to run it? If so, can you post a defconfig and some instructions?  That'll make it easier to test on my end.


I posted a tutorial here on how I test XIP kernel:

https://alexghiti.github.io/xip/XIP.html

If something does not work for you, please tell me.

Alex


+#define XIP_FIXUP(addr) ({                            \
+    uintptr_t __a = (uintptr_t)(addr);                    \
+    (__a >= CONFIG_XIP_PHYS_ADDR && __a < CONFIG_XIP_PHYS_ADDR + SZ_16M) ?    \
+        __a - CONFIG_XIP_PHYS_ADDR + CONFIG_PHYS_RAM_BASE - XIP_OFFSET :\
+        __a;                                \
+    })
+#else
+#define XIP_FIXUP(addr)        (addr)
+#endif /* CONFIG_XIP_KERNEL */
+
  #ifdef CONFIG_MMU
  /* Number of entries in the page global directory */
  #define PTRS_PER_PGD    (PAGE_SIZE / sizeof(pgd_t))


Thank you for doing that!

Alex

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