Hi, all,
On 11/03/2020 03:12 PM, Tiezhu Yang wrote:
In play_dead function, the whole 64-bit PC mailbox was used as a indicator
to determine if the master core had written boot jump information.
However, after we introduced CSR mailsend, the hardware will not guarante
an atomic write for the 64-bit PC mailbox. Thus we have to use the lower
32-bit which is written at the last as the jump indicator instead.
Signed-off-by: Lu Zeng <[email protected]>
Signed-off-by: Jun Yi <[email protected]>
Signed-off-by: Tiezhu Yang <[email protected]>
---
v2: No changes
v3: Update the commit message and comment
arch/mips/loongson64/smp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c
index 736e98d..aa0cd72 100644
--- a/arch/mips/loongson64/smp.c
+++ b/arch/mips/loongson64/smp.c
@@ -764,9 +764,10 @@ static void loongson3_type3_play_dead(int *state_addr)
"1: li %[count], 0x100 \n" /* wait for init loop
*/
"2: bnez %[count], 2b \n" /* limit mailbox
access */
" addiu %[count], -1 \n"
- " ld %[initfunc], 0x20(%[base]) \n" /* get PC via mailbox
*/
I have some confusion here. Play_dead CPUs is always brought up by cpu_up().
On Loongson64, it calls loongson3_boot_secondary(). The value of
startargs[0]
is the address of smp_bootstrap() which is in CKSEG0 and a constant
after the
kernel is compiled. That means its value likes 0xffffffff8... and only
the low
32bit is useful. As "lw" is sign-extended, could we replace "ld" with
"lw" simply?
Thanks,
Jinyang
+ " lw %[initfunc], 0x20(%[base]) \n" /* check lower 32-bit
as jump indicator */
" beqz %[initfunc], 1b \n"
" nop \n"
+ " ld %[initfunc], 0x20(%[base]) \n" /* get PC (whole
64-bit) via mailbox */
" ld $sp, 0x28(%[base]) \n" /* get SP via mailbox
*/
" ld $gp, 0x30(%[base]) \n" /* get GP via mailbox
*/
" ld $a1, 0x38(%[base]) \n"
