[PATCH 0/3] mm/early_ioremap: clarify and clean up early_ioremap_reset()

[PATCH 0/3] mm/early_ioremap: clarify and clean up early_ioremap_reset()

[Sang-Heon Jeon]

__late_set_fixmap() and __late_clear_fixmap() are only used after
early_ioremap_reset() has been called, but the comment above them does
not say anything about that. So arm64, riscv and powerpc, whose
__set_fixmap() works before and after paging_init(), describe the same
situation in three different ways:

                 calls reset    defines the macros
        arm64    yes            yes
        riscv    no             yes
        powerpc  no             no

Patch 1 documents when early_ioremap_reset() needs to be called and
that only architectures calling it need to define the macros.

Patches 2 and 3 remove the unneeded riscv macros, which are
unreachable, and the arm64 reset call and macros, which change
nothing.

No functional change.

Sang-Heon Jeon (3):
  mm/early_ioremap: clarify early_ioremap_reset() semantics
  riscv: remove unused __late_set_fixmap() and __late_clear_fixmap()
  arm64: remove early_ioremap_reset() call and __late_* macros

 arch/arm64/include/asm/fixmap.h |  3 ---
 arch/arm64/kernel/setup.c       |  2 --
 arch/riscv/include/asm/fixmap.h |  3 ---
 mm/early_ioremap.c              | 10 +++++++---
 4 files changed, 7 insertions(+), 11 deletions(-)

-- 
2.43.0


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[PATCH 1/3] mm/early_ioremap: clarify early_ioremap_reset() semantics

[Sang-Heon Jeon]

__late_set_fixmap() and __late_clear_fixmap() are only used after
early_ioremap_reset() has been called.

arm64, riscv and powerpc all have a __set_fixmap() that works before
and after paging_init(), so they do not need to call
early_ioremap_reset() or define the macros, but they describe the same
situation in three different ways:

                 calls reset    defines the macros
        arm64    yes            yes
        riscv    no             yes
        powerpc  no             no

The existing comment is vague and allows all three. Replace it with
comments that make it clear when the reset and the macros are needed.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 mm/early_ioremap.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c
index 96c29b9dc85d..6215b90dfef3 100644
--- a/mm/early_ioremap.c
+++ b/mm/early_ioremap.c
@@ -47,15 +47,19 @@ pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
 	return prot;
 }
 
+/*
+ * Only architectures whose early_ioremap() must stop using __early_set_fixmap()
+ * after paging_init() need to call this.
+ */
 void __init early_ioremap_reset(void)
 {
 	after_paging_init = 1;
 }
 
 /*
- * Generally, ioremap() is available after paging_init() has been called.
- * Architectures wanting to allow early_ioremap after paging_init() can
- * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
+ * Only architectures that call early_ioremap_reset() need to define
+ * __late_set_fixmap() and __late_clear_fixmap(), which early_ioremap() uses
+ * instead of __early_set_fixmap() after the reset.
  */
 #ifndef __late_set_fixmap
 static inline void __init __late_set_fixmap(enum fixed_addresses idx,
-- 
2.43.0


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[PATCH 2/3] riscv: remove unused __late_set_fixmap() and __late_clear_fixmap()

[Sang-Heon Jeon]

__late_set_fixmap() and __late_clear_fixmap() are only used after
early_ioremap_reset() has been called. riscv never calls it because
__set_fixmap() works before and after paging_init(). So remove them.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 arch/riscv/include/asm/fixmap.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
index 0a55099bb734..a81823c5ee4a 100644
--- a/arch/riscv/include/asm/fixmap.h
+++ b/arch/riscv/include/asm/fixmap.h
@@ -55,9 +55,6 @@ enum fixed_addresses {
 
 #define __early_set_fixmap	__set_fixmap
 
-#define __late_set_fixmap	__set_fixmap
-#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
-
 extern void __set_fixmap(enum fixed_addresses idx,
 			 phys_addr_t phys, pgprot_t prot);
 
-- 
2.43.0


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[PATCH 3/3] arm64: remove early_ioremap_reset() call and __late_* macros

[Sang-Heon Jeon]

On arm64, __early_set_fixmap(), __late_set_fixmap() and
__late_clear_fixmap() are all __set_fixmap(). Calling
early_ioremap_reset() changes nothing. So remove the call and the
macros.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 arch/arm64/include/asm/fixmap.h | 3 ---
 arch/arm64/kernel/setup.c       | 2 --
 2 files changed, 5 deletions(-)

diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 65555284446e..abd9800aabf7 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -110,9 +110,6 @@ void __init early_fixmap_init(void);
 
 #define __early_set_fixmap __set_fixmap
 
-#define __late_set_fixmap __set_fixmap
-#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
-
 extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
 
 #include <asm-generic/fixmap.h>
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 23c05dc7a8f2..29c6100f0c50 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -347,8 +347,6 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
 
 	request_standard_resources();
 
-	early_ioremap_reset();
-
 	if (acpi_disabled)
 		psci_dt_init();
 	else
-- 
2.43.0


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