[PATCH v4] arm64: Add purgatory printing
Matthias Brugger
mbrugger at suse.com
Fri Oct 16 07:40:57 EDT 2020
Hi,
On 02/10/2020 20:34, Bhupesh Sharma wrote:
> Hello Matthias,
>
> Thanks for the updated revision.
>
> On Fri, Oct 2, 2020 at 7:13 PM <matthias.bgg at kernel.org> wrote:
>>
>> From: Matthias Brugger <mbrugger at suse.com>
>>
>> Add option to allow purgatory printing on arm64 hardware
>> by passing the console name which should be used.
>> Based on a patch by Geoff Levand.
>>
>> Cc: Geoff Levand <geoff at infradead.org>
>> Signed-off-by: Matthias Brugger <mbrugger at suse.com>
>>
>> ---
>>
>> Changes in v4:
>> - fix snprintf error handling
>>
>> Changes in v3:
>> - check return value of snprintf
>>
>> Changes in v2:
>> - use sizeof(buffer)
>> - user serial command option instead of console
>> - reduce buffer to size 10
>> - use snprintf
>> - fix error handling for wrong serial console parameter
>> - Update help information
>>
>> kexec/arch/arm64/include/arch/options.h | 6 ++-
>> kexec/arch/arm64/kexec-arm64.c | 71 +++++++++++++++++++++++++
>> purgatory/arch/arm64/purgatory-arm64.c | 17 +++++-
>> 3 files changed, 92 insertions(+), 2 deletions(-)
>>
>> diff --git a/kexec/arch/arm64/include/arch/options.h b/kexec/arch/arm64/include/arch/options.h
>> index a17d933..8c695f3 100644
>> --- a/kexec/arch/arm64/include/arch/options.h
>> +++ b/kexec/arch/arm64/include/arch/options.h
>> @@ -5,7 +5,8 @@
>> #define OPT_DTB ((OPT_MAX)+1)
>> #define OPT_INITRD ((OPT_MAX)+2)
>> #define OPT_REUSE_CMDLINE ((OPT_MAX)+3)
>> -#define OPT_ARCH_MAX ((OPT_MAX)+4)
>> +#define OPT_SERIAL ((OPT_MAX)+4)
>> +#define OPT_ARCH_MAX ((OPT_MAX)+5)
>>
>> #define KEXEC_ARCH_OPTIONS \
>> KEXEC_OPTIONS \
>> @@ -13,6 +14,7 @@
>> { "command-line", 1, NULL, OPT_APPEND }, \
>> { "dtb", 1, NULL, OPT_DTB }, \
>> { "initrd", 1, NULL, OPT_INITRD }, \
>> + { "serial", 1, NULL, OPT_SERIAL }, \
>> { "ramdisk", 1, NULL, OPT_INITRD }, \
>> { "reuse-cmdline", 0, NULL, OPT_REUSE_CMDLINE }, \
>>
>> @@ -25,6 +27,7 @@ static const char arm64_opts_usage[] __attribute__ ((unused)) =
>> " --command-line=STRING Set the kernel command line to STRING.\n"
>> " --dtb=FILE Use FILE as the device tree blob.\n"
>> " --initrd=FILE Use FILE as the kernel initial ramdisk.\n"
>> +" --serial=STRING Name of console used for purgatory printing. (e.g. ttyAMA0)\n"
>> " --ramdisk=FILE Use FILE as the kernel initial ramdisk.\n"
>> " --reuse-cmdline Use kernel command line from running system.\n";
>>
>> @@ -32,6 +35,7 @@ struct arm64_opts {
>> const char *command_line;
>> const char *dtb;
>> const char *initrd;
>> + const char *console;
>> };
>>
>> extern struct arm64_opts arm64_opts;
>> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
>> index 45ebc54..6f572ed 100644
>> --- a/kexec/arch/arm64/kexec-arm64.c
>> +++ b/kexec/arch/arm64/kexec-arm64.c
>> @@ -165,6 +165,8 @@ int arch_process_options(int argc, char **argv)
>> break;
>> case OPT_KEXEC_FILE_SYSCALL:
>> do_kexec_file_syscall = 1;
>> + case OPT_SERIAL:
>> + arm64_opts.console = optarg;
>> break;
>> default:
>> break; /* Ignore core and unknown options. */
>> @@ -180,12 +182,72 @@ int arch_process_options(int argc, char **argv)
>> dbgprintf("%s:%d: dtb: %s\n", __func__, __LINE__,
>> (do_kexec_file_syscall && arm64_opts.dtb ? "(ignored)" :
>> arm64_opts.dtb));
>> + dbgprintf("%s:%d: console: %s\n", __func__, __LINE__,
>> + arm64_opts.console);
>> +
>> if (do_kexec_file_syscall)
>> arm64_opts.dtb = NULL;
>>
>> return 0;
>> }
>>
>> +/**
>> + * find_purgatory_sink - Find a sink for purgatory output.
>> + */
>> +
>> +static uint64_t find_purgatory_sink(const char *console)
>> +{
>> + int fd, ret;
>> + char device[255], mem[255];
>> + struct stat sb;
>> + char buffer[10];
>> + uint64_t iomem = 0x0;
>> +
>> + if (!console)
>> + return 0;
>> +
>> + ret = snprintf(device, sizeof(device), "/sys/class/tty/%s", console);
>> + if (ret < 0 || ret >= sizeof(device)) {
>> + fprintf(stderr, "snprintf failed: %s\n", strerror(errno));
>> + return 0;
>> + }
>> +
>> + if (stat(device, &sb) || !S_ISDIR(sb.st_mode)) {
>> + fprintf(stderr, "kexec: %s: No valid console found for %s\n",
>> + __func__, device);
>> + return 0;
>> + }
>> +
>> + ret = snprintf(mem, sizeof(mem), "%s%s", device, "/iomem_base");
>> + if (ret < 0 || ret >= sizeof(mem)) {
>> + fprintf(stderr, "snprintf failed: %s\n", strerror(errno));
>> + return 0;
>> + }
>> +
>> + printf("console memory read from %s\n", mem);
>> +
>> + fd = open(mem, O_RDONLY);
>> + if (fd < 0) {
>> + fprintf(stderr, "kexec: %s: No able to open %s\n",
>> + __func__, mem);
>> + return 0;
>> + }
>> +
>> + memset(buffer, '\0', sizeof(buffer));
>> + ret = read(fd, buffer, sizeof(buffer));
>> + if (ret < 0) {
>> + fprintf(stderr, "kexec: %s: not able to read fd\n", __func__);
>> + close(fd);
>> + return 0;
>> + }
>> +
>> + sscanf(buffer, "%lx", &iomem);
>> + printf("console memory is at %#lx\n", iomem);
>> +
>> + close(fd);
>> + return iomem;
>> +}
>> +
>> /**
>> * struct dtb - Info about a binary device tree.
>> *
>> @@ -637,6 +699,7 @@ int arm64_load_other_segments(struct kexec_info *info,
>> unsigned long hole_min;
>> unsigned long hole_max;
>> unsigned long initrd_end;
>> + uint64_t purgatory_sink;
>> char *initrd_buf = NULL;
>> struct dtb dtb;
>> char command_line[COMMAND_LINE_SIZE] = "";
>> @@ -654,6 +717,11 @@ int arm64_load_other_segments(struct kexec_info *info,
>> command_line[sizeof(command_line) - 1] = 0;
>> }
>>
>> + purgatory_sink = find_purgatory_sink(arm64_opts.console);
>> +
>> + dbgprintf("%s:%d: purgatory sink: 0x%" PRIx64 "\n", __func__, __LINE__,
>> + purgatory_sink);
>> +
>> if (arm64_opts.dtb) {
>> dtb.name = "dtb_user";
>> dtb.buf = slurp_file(arm64_opts.dtb, &dtb.size);
>> @@ -742,6 +810,9 @@ int arm64_load_other_segments(struct kexec_info *info,
>>
>> info->entry = (void *)elf_rel_get_addr(&info->rhdr, "purgatory_start");
>>
>> + elf_rel_set_symbol(&info->rhdr, "arm64_sink", &purgatory_sink,
>> + sizeof(purgatory_sink));
>> +
>> elf_rel_set_symbol(&info->rhdr, "arm64_kernel_entry", &image_base,
>> sizeof(image_base));
>>
>> diff --git a/purgatory/arch/arm64/purgatory-arm64.c b/purgatory/arch/arm64/purgatory-arm64.c
>> index fe50fcf..b4d8578 100644
>> --- a/purgatory/arch/arm64/purgatory-arm64.c
>> +++ b/purgatory/arch/arm64/purgatory-arm64.c
>> @@ -5,15 +5,30 @@
>> #include <stdint.h>
>> #include <purgatory.h>
>>
>> +/* Symbols set by kexec. */
>> +
>> +uint8_t *arm64_sink __attribute__ ((section ("data")));
>> +extern void (*arm64_kernel_entry)(uint64_t, uint64_t, uint64_t, uint64_t);
>> +extern uint64_t arm64_dtb_addr;
>> +
>> void putchar(int ch)
>> {
>> - /* Nothing for now */
>> + if (!arm64_sink)
>> + return;
>> +
>> + *arm64_sink = ch;
>> +
>> + if (ch == '\n')
>> + *arm64_sink = '\r';
>> }
>>
>> void post_verification_setup_arch(void)
>> {
>> + printf("purgatory: booting kernel now\n");
>> }
>>
>> void setup_arch(void)
>> {
>> + printf("purgatory: entry=%lx\n", (unsigned long)arm64_kernel_entry);
>> + printf("purgatory: dtb=%lx\n", arm64_dtb_addr);
>> }
>> --
>> 2.28.0
>
> Looks good to me, so:
> Acked-by: Bhupesh Sharma <bhsharma at redhat.com>
>
Simon: friendly reminder of this patch. Please let me know if you have any
concerns regarding the patch.
Best regards,
Matthias
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