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Sync/lass 20260916 #604

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Merged
hongyuni merged 2 commits into from
Sep 16, 2026
Merged

Sync/lass 20260916 #604

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b1dee1b
lass: detect lass enable via /proc/cpuinfo flag
fanchen2 Aug 26, 2026
7729da3
lass: read full /proc/cmdline when detecting vsyscall mode
fanchen2 Aug 26, 2026
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17 changes: 9 additions & 8 deletions BM/lass/lass.c
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Original file line number Diff line number Diff line change
Expand Up @@ -127,11 +127,11 @@ int cpu_has_lass(void)
return (cpuinfo[0] & (1 << 6));
}

/* Get information from /proc/cmdline */
/* Check the lass flag exposed by the kernel in /proc/cpuinfo */
static bool check_lass_enable(void)
{
char buf[256] = {0};
char command[256] = "cat /proc/cmdline";
char command[256] = "grep -m1 -ow lass /proc/cpuinfo";
bool rv = false;

FILE *cmd = popen(command, "r");
Expand All @@ -141,7 +141,7 @@ static bool check_lass_enable(void)
;
// printf("Get buff:%s\n", buf);
pclose(cmd);
rv = (strstr(buf, " lass") != 0);
rv = (strstr(buf, "lass") != 0);
// printf("%s Get lass! rv:%x\n", __func__, rv);
}

Expand All @@ -151,7 +151,7 @@ static bool check_lass_enable(void)
/* Get information from /proc/cmdline */
static bool check_vsyscall_status(void)
{
char buf[256] = {0};
char buf[4096] = {0};
char command[256] = "cat /proc/cmdline";
bool rv = false;

Expand Down Expand Up @@ -290,9 +290,9 @@ static int test_read_vsys_address(void)
printf("can_read:%d, vsyscall_map_r:%d\n", can_read, vsyscall_map_r);

if (vsyscall_map_r == can_read)
pass_case("Could read vsyscall addr is expected");
pass_case("vsyscall read behavior matches expectation");
else
fail_case("Could not read vsyscall addr is not expected");
fail_case("vsyscall read behavior does not match expectation");

return 0;
}
Expand Down Expand Up @@ -714,9 +714,10 @@ int main(int argc, char *argv[])

if (!check_lass_enable()) {
lass_enable = false;
printf(" under default mode without lass defined in cmdline.\n");
printf(" no lass flag in /proc/cpuinfo, running under default mode without lass.\n");
} else {
lass_enable = true;
}
lass_enable = true;

check_vsyscall_status();

Expand Down
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