Hi Maciej,
> I think you need to find another libc (or the whole userland), as I
> previously suggested.
Indeed. I've replaced it all now.
> > Still left to explain is why the kernel stumbles on registers during
> > initialisation, before user applications are invoked.
>
> Good luck!
The problem was with the inq and outq macros in the Graphics Synthesizer
driver. A 32-bit kernel now works with 32-bit register save/restore and o32
applications, as intended. Many thanks for all your help in finding this!
I've found an unrelated curiosity. With CONFIG_CPU_HAS_MSA undefined,
handle_msa_fpe_int, do_msa_fpe, etc. are still generated with nonsensical
instructions:
80025128 <handle_msa_fpe_int>:
80025128: 787e0859 lq s8,2137(v1) <<<-----
8002512c: 00202821 move a1,at
80025130: 0000040f sync.p
80025134: 40086000 mfc0 t0,c0_sr
...
80030f08 <do_msa_fpe>:
80030f08: 27bdffd8 addiu sp,sp,-40
80030f0c: afb0001c sw s0,28(sp)
80030f10: 00808021 move s0,a0
...
80030f70: 02228824 and s1,s1,v0
80030f74: 02200821 move at,s1
80030f78: 783e0859 lq s8,2137(at) <<<-----
80030f7c: 0000040f sync.p
80030f80: 40016000 mfc0 at,c0_sr
...
I disabled both with the patch below (there seems to be more opportunities
for size reductions overall).
Fredrik
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index ae810da4d499..91855c68e2de 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -439,11 +439,13 @@ NESTED(nmi_handler, PT_SIZE, sp)
TRACE_IRQS_OFF
.endm
+#ifdef CONFIG_CPU_HAS_MSA
.macro __build_clear_msa_fpe
_cfcmsa a1, MSA_CSR
CLI
TRACE_IRQS_OFF
.endm
+#endif
.macro __build_clear_ade
MFC0 t0, CP0_BADVADDR
@@ -503,10 +505,14 @@ NESTED(nmi_handler, PT_SIZE, sp)
BUILD_HANDLER cpu cpu sti silent /* #11 */
BUILD_HANDLER ov ov sti silent /* #12 */
BUILD_HANDLER tr tr sti silent /* #13 */
+#ifdef CONFIG_CPU_HAS_MSA
BUILD_HANDLER msa_fpe msa_fpe msa_fpe silent /* #14 */
+#endif
BUILD_HANDLER fpe fpe fpe silent /* #15 */
BUILD_HANDLER ftlb ftlb none silent /* #16 */
+#ifdef CONFIG_CPU_HAS_MSA
BUILD_HANDLER msa msa sti silent /* #21 */
+#endif
BUILD_HANDLER mdmx mdmx sti silent /* #22 */
#ifdef CONFIG_HARDWARE_WATCHPOINTS
/*
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 38dfa27730ff..9bd7b4a0b764 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1457,6 +1457,7 @@ asmlinkage void do_cpu(struct pt_regs *regs)
exception_exit(prev_state);
}
+#ifdef CONFIG_CPU_HAS_MSA
asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
{
enum ctx_state prev_state;
@@ -1497,6 +1498,7 @@ asmlinkage void do_msa(struct pt_regs *regs)
out:
exception_exit(prev_state);
}
+#endif /* CONFIG_CPU_HAS_MSA */
asmlinkage void do_mdmx(struct pt_regs *regs)
{
@@ -2425,7 +2427,9 @@ void __init trap_init(void)
set_except_vector(EXCCODE_CPU, handle_cpu);
set_except_vector(EXCCODE_OV, handle_ov);
set_except_vector(EXCCODE_TR, handle_tr);
+#ifdef CONFIG_CPU_HAS_MSA
set_except_vector(EXCCODE_MSAFPE, handle_msa_fpe);
+#endif
if (current_cpu_type() == CPU_R6000 ||
current_cpu_type() == CPU_R6000A) {
@@ -2455,7 +2459,9 @@ void __init trap_init(void)
set_except_vector(EXCCODE_TLBXI, tlb_do_page_fault_0);
}
+#ifdef CONFIG_CPU_HAS_MSA
set_except_vector(EXCCODE_MSADIS, handle_msa);
+#endif
set_except_vector(EXCCODE_MDMX, handle_mdmx);
if (cpu_has_mcheck)
