On 11.08.20 08:20, Rick Chen wrote:
Hi Heinrich
From: Heinrich Schuchardt [mailto:xypron.glpk@gmx.de] Sent: Tuesday, August 11, 2020 11:57 AM To: Rick Jian-Zhi Chen(陳建志) Cc: Sean Anderson; Lukas Auer; Simon Glass; Anup Patel; Daniel Schwierzeck; u-boot@lists.denx.de; Heinrich Schuchardt Subject: [PATCH 1/1] riscv: don't jump to 0x0 in handle_ipi()
At least on the Kendryte K210:
gd->arch.available_harts= 0x0000000000000003 arch.ipi[0].addr= gd->0x0000000000000000 arch.ipi[0].arg0= 0x0000000000000000 gd->arch.ipi[0].arg1= 0x0000000000000000 arch.ipi[1].addr= gd->0x0000000000000000 arch.ipi[1].arg0= 0x0000000000000000 gd->arch.ipi[1].arg1= 0x0000000000000000
We should not jump to 0x0 to handle an interrupt.
Can you explain why K210 be affected by it ?
I have been running U-Boot on the MaixDuino.
Without this patch secondary_hart_loop() is reached only once. With the patch it is reached several thousand times.
I would not expect NULL to contain any code that should be executed by the secondary hart. See doc/board/sipeed/maix.rst:
Address Size Description ========== ========= =========== 0x00000000 0x1000 debug 0x00001000 0x1000 rom 0x02000000 0xC000 clint
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de
arch/riscv/lib/smp.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c index ac22136314..d725fa32e8 100644 --- a/arch/riscv/lib/smp.c +++ b/arch/riscv/lib/smp.c @@ -96,6 +96,8 @@ void handle_ipi(ulong hart) return; }
if (!smp_function)return; smp_function(hart, gd->arch.ipi[hart].arg0, gd->arch.ipi[hart].arg1); }I remember Sean add this check in [v10,14/21] riscv: Clean up IPI initialization code . And I ask him to remove. https://patchwork.ozlabs.org/project/uboot/patch/20200503024637.327733-15-se...
Your comment was: "Please remove the sanity check. If zero address is the intended jump point, then system will work abnormal."
The only place where gd->arch.ipi[hart].addr is set is:
arch/riscv/lib/smp.c:53 send_ipi_many(): gd->arch.ipi[reg].addr = ipi->addr;
send_ipi_many() is only called in smp_call_function().
So the line
smp_function(hart, gd->arch.ipi[hart].arg0, gd->arch.ipi[hart].arg1);
can only work if smp_function() has been called before this point at any time. The start code only calls it in spl_secondary_hart_stack_gd_setup().
Why do we call handle_ipi() on the secondary hart at all?
Where do you expect it to jump if U-Boot is the first binary loaded?
Even if spl_secondary_hart_stack_gd_setup() has initialized the jump address to secondary_hart_relocate(), do we want the secondary hart to execute it again and again?
Best regards
Heinrich