Le 23/05/2019 à 08:14, Paul Mackerras a écrit :
On Tue, Apr 30, 2019 at 12:39:03PM +0000, Christophe Leroy wrote:
This patch implements a fast entry for syscalls.
Syscalls don't have to preserve non volatile registers except LR.
This patch then implement a fast entry for syscalls, where
volatile registers get clobbered.
As this entry is dedicated to syscall it always sets MSR_EE
and warns in case MSR_EE was previously off
It also assumes that the call is always from user, system calls are
unexpected from kernel.
This is now upstream as commit 1a4b739bbb4f. On the e500mc test
config that I use, I'm getting this build failure:
Is that a standard defconfig ? If not, can you provide your .config ?
arch/powerpc/kernel/head_fsl_booke.o: In function `SystemCall':
arch/powerpc/kernel/head_fsl_booke.S:416: undefined reference to
`kvmppc_handler_BOOKE_INTERRUPT_SYSCALL_SPRN_SRR1'
Makefile:1052: recipe for target 'vmlinux' failed
+.macro SYSCALL_ENTRY trapno intno
+ mfspr r10, SPRN_SPRG_THREAD
+#ifdef CONFIG_KVM_BOOKE_HV
+BEGIN_FTR_SECTION
+ mtspr SPRN_SPRG_WSCRATCH0, r10
+ stw r11, THREAD_NORMSAVE(0)(r10)
+ stw r13, THREAD_NORMSAVE(2)(r10)
+ mfcr r13 /* save CR in r13 for now */
+ mfspr r11, SPRN_SRR1
+ mtocrf 0x80, r11 /* check MSR[GS] without clobbering reg */
+ bf 3, 1975f
+ b kvmppc_handler_BOOKE_INTERRUPT_\intno\()_SPRN_SRR1
It seems to me that the "_SPRN_SRR1" on the end of this line
isn't meant to be there... However, it still fails to link with that
removed.
This SYSCALL_ENTRY macro is a slimmed version of NORMAL_EXCEPTION_PROLOG()
In NORMAL_EXCEPTION_PROLOG(), we have:
DO_KVM BOOKE_INTERRUPT_##intno SPRN_SRR1;
The _SPRN_SRR1 comes from there
Then in /arch/powerpc/include/asm/kvm_booke_hv_asm.h:
.macro DO_KVM intno srr1
#ifdef CONFIG_KVM_BOOKE_HV
BEGIN_FTR_SECTION
mtocrf 0x80, r11 /* check MSR[GS] without clobbering reg */
bf 3, 1975f
b kvmppc_handler_\intno\()_\srr1
1975:
END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
#endif
.endm
Christophe
