[PATCHv3 1/4] arm64: make phys_offset signed

[Simon Horman]

On Tue, Dec 28, 2021 at 09:26:56PM +0800, Pingfan Liu wrote:
> After kernel commit 7bc1a0f9e176 ("arm64: mm: use single quantity to
> represent the PA to VA translation"), phys_offset can be negative if
> running 52-bits kernel on 48-bits hardware.
> 
> So changing phys_offset from unsigned to signed.
> 
> Signed-off-by: Pingfan Liu <piliu at redhat.com>
> Cc: Kairui Song <kasong at tencent.com>
> Cc: Simon Horman <horms at verge.net.au>
> Cc: Philipp Rudo <prudo at redhat.com>
> To: kexec at lists.infradead.org
> ---
>  kexec/arch/arm64/kexec-arm64.c | 8 ++++----
>  kexec/arch/arm64/kexec-arm64.h | 2 +-
>  util_lib/elf_info.c            | 2 +-
>  util_lib/include/elf_info.h    | 2 +-
>  4 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
> index 6f572ed..7373fa3 100644
> --- a/kexec/arch/arm64/kexec-arm64.c
> +++ b/kexec/arch/arm64/kexec-arm64.c
> @@ -859,7 +859,7 @@ void add_segment(struct kexec_info *info, const void *buf, size_t bufsz,
>  	add_segment_phys_virt(info, buf, bufsz, base, memsz, 1);
>  }
>  
> -static inline void set_phys_offset(uint64_t v, char *set_method)
> +static inline void set_phys_offset(long v, char *set_method)

Perhaps it would be more in keeping with the current implementation
to use int64_t rather than long ?

>  {
>  	if (arm64_mem.phys_offset == arm64_mem_ngv
>  		|| v < arm64_mem.phys_offset) {
> @@ -928,7 +928,7 @@ static int get_page_offset(void)
>   * from VMCOREINFO note inside 'kcore'.
>   */
>  
> -static int get_phys_offset_from_vmcoreinfo_pt_note(unsigned long *phys_offset)
> +static int get_phys_offset_from_vmcoreinfo_pt_note(long *phys_offset)
>  {
>  	int fd, ret = 0;
>  
> @@ -948,7 +948,7 @@ static int get_phys_offset_from_vmcoreinfo_pt_note(unsigned long *phys_offset)
>   * from PT_LOADs inside 'kcore'.
>   */
>  
> -int get_phys_base_from_pt_load(unsigned long *phys_offset)
> +int get_phys_base_from_pt_load(long *phys_offset)
>  {
>  	int i, fd, ret;
>  	unsigned long long phys_start;
> @@ -997,7 +997,7 @@ static bool to_be_excluded(char *str)
>  int get_memory_ranges(struct memory_range **range, int *ranges,
>  	unsigned long kexec_flags)
>  {
> -	unsigned long phys_offset = UINT64_MAX;
> +	long phys_offset = (long)UINT64_MAX;

Effectively this sets phys_offset to -1.
Is that ok / intended ? If so, perhaps it's clearer to just use -1.

Regardless, can clean up other uses of long with UINT64_MAX introduced
by this patch?

I see the following:

make
...
kexec/arch/arm64/kexec-arm64.c: In function ‘get_memory_ranges’:
kexec/arch/arm64/kexec-arm64.c:1022:20: warning: comparison between signed and u
nsigned integer expressions [-Wsign-compare]
    if (phys_offset != UINT64_MAX)
...
kexec/arch/arm64/kexec-arm64.c:1034:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (phys_offset != UINT64_MAX)


>  	FILE *fp;
>  	const char *iomem = proc_iomem();
>  	char line[MAX_LINE], *str;
> diff --git a/kexec/arch/arm64/kexec-arm64.h b/kexec/arch/arm64/kexec-arm64.h
> index ed447ac..1844b67 100644
> --- a/kexec/arch/arm64/kexec-arm64.h
> +++ b/kexec/arch/arm64/kexec-arm64.h
> @@ -58,7 +58,7 @@ extern off_t initrd_size;
>   */
>  
>  struct arm64_mem {
> -	uint64_t phys_offset;
> +	long phys_offset;
>  	uint64_t text_offset;
>  	uint64_t image_size;
>  	uint64_t vp_offset;
> diff --git a/util_lib/elf_info.c b/util_lib/elf_info.c
> index 51d8b92..5574c7f 100644
> --- a/util_lib/elf_info.c
> +++ b/util_lib/elf_info.c
> @@ -1236,7 +1236,7 @@ int read_elf(int fd)
>  	return 0;
>  }
>  
> -int read_phys_offset_elf_kcore(int fd, unsigned long *phys_off)
> +int read_phys_offset_elf_kcore(int fd, long *phys_off)
>  {
>  	int ret;
>  
> diff --git a/util_lib/include/elf_info.h b/util_lib/include/elf_info.h
> index 4bc9279..f550d86 100644
> --- a/util_lib/include/elf_info.h
> +++ b/util_lib/include/elf_info.h
> @@ -28,7 +28,7 @@ int get_pt_load(int idx,
>  	unsigned long long *phys_end,
>  	unsigned long long *virt_start,
>  	unsigned long long *virt_end);
> -int read_phys_offset_elf_kcore(int fd, unsigned long *phys_off);
> +int read_phys_offset_elf_kcore(int fd, long *phys_off);
>  int read_elf(int fd);
>  void dump_dmesg(int fd, void (*handler)(char*, unsigned int));
>  
> -- 
> 2.31.1
>