compel: add APIs to get stack pointers

We need to know what are stack pointers of every thread to ensure that the
current stack page will not be treated as lazy.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Alice Frosi <alice@linux.vnet.ibm.com>
Reviewed-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>

compel/arch/aarch64/src/lib/include/uapi/asm/infect-types.h

@@ -20,6 +20,7 @@ typedef struct user_fpsimd_state	user_fpregs_struct_t;
 
 #define REG_RES(r)			((uint64_t)(r).regs[0])
 #define REG_IP(r)			((uint64_t)(r).pc)
+#define REG_SP(r)			((uint64_t)((r).sp))
 #define REG_SYSCALL_NR(r)		((uint64_t)(r).regs[8])
 
 #define user_regs_native(pregs)			true

compel/arch/arm/src/lib/include/uapi/asm/infect-types.h

@@ -54,6 +54,7 @@ struct user_vfp_exc {
 
 #define REG_RES(regs)		((regs).ARM_r0)
 #define REG_IP(regs)		((regs).ARM_pc)
+#define REG_SP(regs)		((regs).ARM_sp)
 #define REG_SYSCALL_NR(regs)	((regs).ARM_r7)
 
 #define user_regs_native(pregs)			true

compel/arch/ppc64/src/lib/include/uapi/asm/infect-types.h

@@ -74,6 +74,7 @@ typedef struct {
 
 #define REG_RES(regs)		((uint64_t)(regs).gpr[3])
 #define REG_IP(regs)		((uint64_t)(regs).nip)
+#define REG_SP(regs)		((uint64_t)(regs).gpr[1])
 #define REG_SYSCALL_NR(regs)	((uint64_t)(regs).gpr[0])
 
 #define user_regs_native(pregs)			true

compel/arch/s390/src/lib/include/uapi/asm/infect-types.h

@@ -64,6 +64,7 @@ typedef struct {
 
 #define REG_RES(r)			((uint64_t)(r).prstatus.gprs[2])
 #define REG_IP(r)			((uint64_t)(r).prstatus.psw.addr)
+#define REG_SP(r)			((uint64_t)(r).prstatus.gprs[15])
 /*
  * We assume that REG_SYSCALL_NR() is only used for pie code where we
  * always use svc 0 with opcode in %r1.

compel/arch/x86/src/lib/include/uapi/asm/infect-types.h

@@ -111,6 +111,7 @@ typedef struct xsave_struct user_fpregs_struct_t;
 
 #define REG_RES(regs)		get_user_reg(&regs, ax)
 #define REG_IP(regs)		get_user_reg(&regs, ip)
+#define REG_SP(regs)		get_user_reg(&regs, sp)
 #define REG_SYSCALL_NR(regs)	get_user_reg(&regs, orig_ax)
 
 #define __NR(syscall, compat)	((compat) ? __NR32_##syscall : __NR_##syscall)

compel/include/uapi/infect.h

@@ -165,4 +165,7 @@ extern void compel_relocs_apply(void *mem, void *vbase, size_t size, compel_relo
 
 extern unsigned long compel_task_size(void);
 
+extern uint64_t compel_get_leader_sp(struct parasite_ctl *ctl);
+extern uint64_t compel_get_thread_sp(struct parasite_thread_ctl *tctl);
+
 #endif

compel/src/lib/infect.c

@@ -1585,3 +1585,13 @@ struct parasite_blob_desc *compel_parasite_blob_desc(struct parasite_ctl *ctl)
 {
 	return &ctl->pblob;
 }
+
+uint64_t compel_get_leader_sp(struct parasite_ctl *ctl)
+{
+	return REG_SP(ctl->orig.regs);
+}
+
+uint64_t compel_get_thread_sp(struct parasite_thread_ctl *tctl)
+{
+	return REG_SP(tctl->th.regs);
+}