riscv: Fixup mix rv64 & rv32 running

[  559.348135] run_ltp.sh[186]: unhandled signal 11 code 0x1 at 0x00000000ff91bca0 in busybox[10000+13d000]
[  559.358679] CPU: 0 PID: 186 Comm: run_ltp.sh Not tainted 5.10.4 #3
[  559.365135] epc: 000000000008d67e ra : 000000000008d674 sp : 0000003fff91bca0
[  559.372457]  gp : 0000000000150548 tp : 00000000001537a0 t0 : 0000000000000000
[  559.379856]  t1 : 2f2f2f2f2f2f2f2f t2 : 000000000000006a s0 : 0000000000154798
[  559.387225]  s1 : 0000000000141eef a0 : 000000000008e4a0 a1 : 00000000001547f0
[  559.394598]  a2 : 0000000000154810 a3 : 000000000000002f a4 : 000000000000002f
[  559.401969]  a5 : 0000000000000000 a6 : 7efefefefefefeff a7 : 00000000000000dd
[  559.409333]  s2 : 0000000000103960 s3 : 0000000000000008 s4 : 0000000000153828
[  559.416696]  s5 : 0000000000000000 s6 : 00000000001547d0 s7 : 0000000000000000
[  559.425234]  s8 : 0000000000000000 s9 : 0000000000157fc0 s10: 00000000001547f0
[  559.432662]  s11: 0000000000000001 t3 : ffffffffffffffff t4 : 0000003ff683e1a8
[  559.440022]  t5 : 0000000000000005 t6 : ffffffffffffffff
[  559.445504] status: 8000000100006620 badaddr: 00000000ff91bca0 cause: 000000000000000d
Segmentation fault

The status shows in UXL_32 mmde, but busybox is 64bit elf.

Signed-off-by: Guo Ren <[email protected]>

Author: guoren83

arch/riscv/include/asm/elf.h

@@ -113,9 +113,6 @@ do {    if ((ex).e_ident[EI_CLASS] == ELFCLASS32)		\
 typedef compat_ulong_t			compat_elf_greg_t;
 typedef compat_elf_greg_t		compat_elf_gregset_t[ELF_NGREG];
 
-#define compat_start_thread		compat_start_thread
-
-
 extern int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
 					      int uses_interp);
 #define compat_arch_setup_additional_pages \

arch/riscv/include/asm/processor.h

@@ -67,9 +67,6 @@ extern void start_thread(struct pt_regs *regs,
 			unsigned long pc, unsigned long sp);
 
 #ifdef CONFIG_COMPAT
-extern void compat_start_thread(struct pt_regs *regs,
-				unsigned long pc, unsigned long sp);
-
 #define DEFAULT_MAP_WINDOW_64 TASK_SIZE_64
 #else
 #define DEFAULT_MAP_WINDOW_64 TASK_SIZE

arch/riscv/kernel/process.c

@@ -18,6 +18,7 @@
 
 #include <asm/unistd.h>
 #include <asm/processor.h>
+#include <asm/compat.h>
 #include <asm/csr.h>
 #include <asm/string.h>
 #include <asm/switch_to.h>
@@ -91,16 +92,15 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
 
 	regs->epc = pc;
 	regs->sp = sp;
-}
 
 #ifdef CONFIG_COMPAT
-void compat_start_thread(struct pt_regs *regs, unsigned long pc,
-			 unsigned long sp)
-{
-	start_thread(regs, pc, sp);
-	regs->status |= SR_UXL_32;
-}
+	regs->status &= ~SR_UXL;
+	if (is_compat_task())
+		regs->status |= SR_UXL_32;
+	else
+		regs->status |= SR_UXL_64;
 #endif
+}
 
 void flush_thread(void)
 {