On 2022/11/12 5:50, Mark Brown wrote:
+// Trivial memory copy: copy x2 bytes, starting at address x1, to address x0. +// Clobbers x0-x3 +function memcpy + cmp x2, #0 + b.eq 1f +0: ldrb w3, [x1], #1 + strb w3, [x0], #1 + subs x2, x2, #1 + b.ne 0b +1: ret +endfunction
There is an exact same implementation of memcpy in fp/asm-utils.S.
+ +// Generate a test pattern for storage in ZT +// x0: pid +// x1: generation + +// These values are used to constuct a 32-bit pattern that is repeated in the
s/constuct/construct/ ?
+// scratch buffer as many times as will fit: +// bits 31:24 generation number (increments once per test_loop) +// bits 23: 8 pid +// bits 7: 0 32-bit lane index + +function pattern + mov w3, wzr + bfi w3, w0, #8, #16 // PID + bfi w3, w1, #24, #8 // Generation + + ldr x0, =scratch + mov w1, #ZT_B / 4 + +0: str w3, [x0], #4 + add w3, w3, #1 // Lane + subs w1, w1, #1 + b.ne 0b + + ret +endfunction + +// Set up test pattern in a ZT horizontal vector +// x0: pid +// x1: generation +function setup_zt + mov x4, x30 + + bl pattern // Get pattern in scratch buffer + ldr x0, =ztref + ldr x1, =scratch + mov x2, #ZT_B + bl memcpy + + _ldr_zt 0 // load zt0 from pointer x0
Isn't x0 already clobbered by memcpy (and is now pointing to the end of ztref)?
+ + ret x4 +endfunction + +// Trivial memory compare: compare x2 bytes starting at address x0 with +// bytes starting at address x1. +// Returns only if all bytes match; otherwise, the program is aborted. +// Clobbers x0-x5. +function memcmp + cbz x2, 2f + + stp x0, x1, [sp, #-0x20]! + str x2, [sp, #0x10] + + mov x5, #0 +0: ldrb w3, [x0, x5] + ldrb w4, [x1, x5] + add x5, x5, #1 + cmp w3, w4 + b.ne 1f + subs x2, x2, #1 + b.ne 0b + +1: ldr x2, [sp, #0x10] + ldp x0, x1, [sp], #0x20 + b.ne barf + +2: ret +endfunction + +// Verify that a ZT vector matches its shadow in memory, else abort +// Clobbers x0-x7 and x12.
It looks like check_zt doesn't clobber as many registers as "x0-x7 and x12".
+function check_zt + mov x3, x30 + + ldr x0, =scratch // Poison scratch + mov x1, #ZT_B + bl memfill_ae + + ldr x0, =scratch + _str_zt 0 + + ldr x0, =ztref + ldr x1, =scratch + mov x2, #ZT_B + mov x30, x3 + b memcmp +endfunction
[...]
+.Ltest_loop: + mov x0, x20 + mov x1, x22 + bl setup_zt + + mov x8, #__NR_sched_yield // Encourage preemption + svc #0 + + mov x0, x20 + mov x1, x22
check_zt receives no parameter so there is no need to initialize x0 and x1.
+ bl check_zt + + add x22, x22, #1 // Everything still working + b .Ltest_loop + +.Labort: + mov x0, #0 + mov x1, #SIGABRT + mov x8, #__NR_kill + svc #0 +endfunction
[...]
+function svcr_barf
And svcr_barf is unused in zt-test. Zenghui
