Compressed/Makefile does not have "-Wall" flag, this is the old problem of
x86 not sharing makefiles. Fix by adding "-Wall" flag to Makefile. But when
"-Wall" flag added to Makefile, a few extra warnings were found.
1.
In file included from arch/x86/boot/compressed/misc.c:15:
In file included from arch/x86/boot/compressed/misc.h:24:
In file included from ./include/linux/elf.h:6:
In file included from ./arch/x86/include/asm/elf.h:8:
In file included from ./include/linux/thread_info.h:60:
./arch/x86/include/asm/thread_info.h:175:13: warning: calling
"__builtin_frame_address" with a nonzero argument is unsafe
[-Wframe-address]
oldframe = __builtin_frame_address(1);
^~~~~~~~~~~~~~~~~~~~~~~~~~
./arch/x86/include/asm/thread_info.h:177:11: warning: calling
"__builtin_frame_address" with a nonzero argument is unsafe
[-Wframe-address]
frame = __builtin_frame_address(2);
^~~~~~~~~~~~~~~~~~~~~~~~~~
This warning is disabled in the main Makefile for this reason so we
should just be able to disable it, adding "frame-address" flag to
Makefile.
2.
arch/x86/boot/compressed/kaslr.c:627:6: warning: unused variable
"i" [-Wunused-variable]
int i;
^
This happens when CONFIG_MEMORY_HOTREMOVE or CONFIG_ACPI are "n".
Fix by adding "-std=gnu11" flag to Makefile, and we should put
the variable "i" within the for loop.
3.
arch/x86/boot/compressed/acpi.c:23:1: warning: unused function
"__efi_get_rsdp_addr" [-Wunused-function]
This happens when CONFIG_EFI is disabled for the reason that
function "__efi_get_rsdp_addr" is only called in efi_get_rsdp_addr
when CONFIG_EFI enable. So function "__efi_get_rsdp_addr" should
not be defined when CONFIG_EFI is disabled.
Signed-off-by: Li Zetao <lizetao1@huawei.com>
---
v1 -> v2: Patch is new
v2 -> v3: Resolve extra warnings after "-Wall" flag added
v3 -> v4: Put this patch at the end
arch/x86/boot/compressed/Makefile | 3 ++-
arch/x86/boot/compressed/acpi.c | 5 +++--
arch/x86/boot/compressed/kaslr.c | 3 +--
3 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 3a261abb6d15..8918a8306dff 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -35,7 +35,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
# be valid.
KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS)
KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
-KBUILD_CFLAGS += -Wundef
+KBUILD_CFLAGS += -Wundef -Wall -std=gnu11
KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
cflags-$(CONFIG_X86_32) := -march=i386
cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone
@@ -44,6 +44,7 @@ KBUILD_CFLAGS += -mno-mmx -mno-sse
KBUILD_CFLAGS += -ffreestanding -fshort-wchar
KBUILD_CFLAGS += -fno-stack-protector
KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
+KBUILD_CFLAGS += $(call cc-disable-warning, frame-address)
KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
KBUILD_CFLAGS += -Wno-pointer-sign
KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index 21febd9f21ab..c062a8230e9c 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -19,10 +19,10 @@
*/
struct mem_vector immovable_mem[MAX_NUMNODES*2];
+#ifdef CONFIG_EFI
static acpi_physical_address
__efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)
{
-#ifdef CONFIG_EFI
unsigned long rsdp_addr;
/*
@@ -41,9 +41,10 @@ __efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)
return (acpi_physical_address)rsdp_addr;
debug_putstr("Error getting RSDP address.\n");
-#endif
+
return 0;
}
+#endif
static acpi_physical_address efi_get_rsdp_addr(void)
{
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index e476bcbd9b42..4abc9c42cf4d 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -625,7 +625,6 @@ static bool process_mem_region(struct mem_vector *region,
unsigned long minimum,
unsigned long image_size)
{
- int i;
/*
* If no immovable memory found, or MEMORY_HOTREMOVE disabled,
* use @region directly.
@@ -645,7 +644,7 @@ static bool process_mem_region(struct mem_vector *region,
* If immovable memory found, filter the intersection between
* immovable memory and @region.
*/
- for (i = 0; i < num_immovable_mem; i++) {
+ for (int i = 0; i < num_immovable_mem; i++) {
u64 start, end, entry_end, region_end;
struct mem_vector entry;
--
2.34.1On Tue, Oct 11, 2022 at 01:29:04AM +0000, Li Zetao wrote:
> This warning is disabled in the main Makefile for this reason so we
Who's "we"?
Please use passive voice in your commit message: no "we" or "I", etc,
and describe your changes in imperative mood.
Also, pls read section "2) Describe your changes" in
Documentation/process/submitting-patches.rst for more details.
Also, see section "Changelog" in
Documentation/process/maintainer-tip.rst
Bottom line is: personal pronouns are ambiguous in text, especially with
so many parties/companies/etc developing the kernel so let's avoid them
please.
In any case, it is getting there but this is not how you structure a
patchset like this. The proper order is:
1st patch: Remove unused variables
2nd patch: Fix -Wframe-address warning and explain why
3rd patch: Fix arch/x86/boot/compressed/acpi.c:23:1: warning: unused function "__efi_get_rsdp_addr" [-Wunused-function]
Btw, I also get with -Wall
In function ‘find_trampoline_placement’,
inlined from ‘paging_prepare’ at arch/x86/boot/compressed/pgtable_64.c:135:35:
arch/x86/boot/compressed/pgtable_64.c:60:30: warning: array subscript 0 is outside array bounds of ‘short unsigned int[0]’ [-Warray-bounds]
60 | ebda_start = *(unsigned short *)0x40e << 4;
| ^~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/boot/compressed/pgtable_64.c:61:30: warning: array subscript 0 is outside array bounds of ‘short unsigned int[0]’ [-Warray-bounds]
61 | bios_start = *(unsigned short *)0x413 << 10;
| ^~~~~~~~~~~~~~~~~~~~~~~~
In function ‘bios_get_rsdp_addr’,
inlined from ‘get_rsdp_addr’ at arch/x86/boot/compressed/acpi.c:163:8:
arch/x86/boot/compressed/acpi.c:130:19: warning: array subscript 0 is outside array bounds of ‘u16[0]’ {aka ‘short unsigned int[]’} [-Warray-bounds]
130 | address = *(u16 *)ACPI_EBDA_PTR_LOCATION;
That should be a separate patch too.
Nth patch(es): Fix more warnings after building at least
"allnoconfig" "defconfig" "allmodconfig" "allyesconfig"
for both 32-bit and 64-bit. A bunch of randconfigs on a big machine
would help a lot.
N + kth patch: Add -std=gnu11
X. Final patch: Add -Wall to compressed/Makefile.
In that order so that no warnings are seen when doing random builds.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On Mon, Oct 10, 2022 at 6:32 PM Li Zetao <lizetao1@huawei.com> wrote:
>
> Compressed/Makefile does not have "-Wall" flag, this is the old problem of
> x86 not sharing makefiles. Fix by adding "-Wall" flag to Makefile. But when
> "-Wall" flag added to Makefile, a few extra warnings were found.
>
> 1.
> In file included from arch/x86/boot/compressed/misc.c:15:
> In file included from arch/x86/boot/compressed/misc.h:24:
> In file included from ./include/linux/elf.h:6:
> In file included from ./arch/x86/include/asm/elf.h:8:
> In file included from ./include/linux/thread_info.h:60:
> ./arch/x86/include/asm/thread_info.h:175:13: warning: calling
> "__builtin_frame_address" with a nonzero argument is unsafe
> [-Wframe-address]
> oldframe = __builtin_frame_address(1);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~
>
> ./arch/x86/include/asm/thread_info.h:177:11: warning: calling
> "__builtin_frame_address" with a nonzero argument is unsafe
> [-Wframe-address]
> frame = __builtin_frame_address(2);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~
>
> This warning is disabled in the main Makefile for this reason so we
> should just be able to disable it, adding "frame-address" flag to
> Makefile.
>
> 2.
> arch/x86/boot/compressed/kaslr.c:627:6: warning: unused variable
> "i" [-Wunused-variable]
> int i;
> ^
>
> This happens when CONFIG_MEMORY_HOTREMOVE or CONFIG_ACPI are "n".
> Fix by adding "-std=gnu11" flag to Makefile, and we should put
> the variable "i" within the for loop.
>
> 3.
> arch/x86/boot/compressed/acpi.c:23:1: warning: unused function
> "__efi_get_rsdp_addr" [-Wunused-function]
>
> This happens when CONFIG_EFI is disabled for the reason that
> function "__efi_get_rsdp_addr" is only called in efi_get_rsdp_addr
> when CONFIG_EFI enable. So function "__efi_get_rsdp_addr" should
> not be defined when CONFIG_EFI is disabled.
>
> Signed-off-by: Li Zetao <lizetao1@huawei.com>
I gave this a quick spin with clang to ensure that I didn't observe
new warnings produced via -Wall:
$ make LLVM=1 -j128 -s defconfig all
$ make LLVM=1 ARCH=i386 -j128 -s defconfig all
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> v1 -> v2: Patch is new
> v2 -> v3: Resolve extra warnings after "-Wall" flag added
> v3 -> v4: Put this patch at the end
>
> arch/x86/boot/compressed/Makefile | 3 ++-
> arch/x86/boot/compressed/acpi.c | 5 +++--
> arch/x86/boot/compressed/kaslr.c | 3 +--
> 3 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
> index 3a261abb6d15..8918a8306dff 100644
> --- a/arch/x86/boot/compressed/Makefile
> +++ b/arch/x86/boot/compressed/Makefile
> @@ -35,7 +35,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
> # be valid.
> KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS)
> KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
> -KBUILD_CFLAGS += -Wundef
> +KBUILD_CFLAGS += -Wundef -Wall -std=gnu11
> KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
> cflags-$(CONFIG_X86_32) := -march=i386
> cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone
> @@ -44,6 +44,7 @@ KBUILD_CFLAGS += -mno-mmx -mno-sse
> KBUILD_CFLAGS += -ffreestanding -fshort-wchar
> KBUILD_CFLAGS += -fno-stack-protector
> KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
> +KBUILD_CFLAGS += $(call cc-disable-warning, frame-address)
> KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
> KBUILD_CFLAGS += -Wno-pointer-sign
> KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
> diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
> index 21febd9f21ab..c062a8230e9c 100644
> --- a/arch/x86/boot/compressed/acpi.c
> +++ b/arch/x86/boot/compressed/acpi.c
> @@ -19,10 +19,10 @@
> */
> struct mem_vector immovable_mem[MAX_NUMNODES*2];
>
> +#ifdef CONFIG_EFI
> static acpi_physical_address
> __efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)
> {
> -#ifdef CONFIG_EFI
> unsigned long rsdp_addr;
>
> /*
> @@ -41,9 +41,10 @@ __efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)
> return (acpi_physical_address)rsdp_addr;
>
> debug_putstr("Error getting RSDP address.\n");
> -#endif
> +
> return 0;
> }
> +#endif
>
> static acpi_physical_address efi_get_rsdp_addr(void)
> {
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index e476bcbd9b42..4abc9c42cf4d 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -625,7 +625,6 @@ static bool process_mem_region(struct mem_vector *region,
> unsigned long minimum,
> unsigned long image_size)
> {
> - int i;
> /*
> * If no immovable memory found, or MEMORY_HOTREMOVE disabled,
> * use @region directly.
> @@ -645,7 +644,7 @@ static bool process_mem_region(struct mem_vector *region,
> * If immovable memory found, filter the intersection between
> * immovable memory and @region.
> */
> - for (i = 0; i < num_immovable_mem; i++) {
> + for (int i = 0; i < num_immovable_mem; i++) {
> u64 start, end, entry_end, region_end;
> struct mem_vector entry;
>
> --
> 2.34.1
>
--
Thanks,
~Nick Desaulniers
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