Merge tag 'riscv-for-linus-5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:
 "I have a few KGDB-related fixes. They're mostly fixes for build
  warnings, but there's also:

   - Support for the qSupported and qXfer packets, which are necessary
     to pass around GDB XML information which we need for the RISC-V GDB
     port to fully function.

   - Users can now select STRICT_KERNEL_RWX instead of forcing it on"

* tag 'riscv-for-linus-5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Avoid kgdb.h including gdb_xml.h to solve unused-const-variable warning
  kgdb: Move the extern declaration kgdb_has_hit_break() to generic kgdb.h
  riscv: Fix "no previous prototype" compile warning in kgdb.c file
  riscv: enable the Kconfig prompt of STRICT_KERNEL_RWX
  kgdb: enable arch to support XML packet.

Author: torvalds

arch/riscv/Kconfig

@@ -23,6 +23,8 @@ config RISCV
 	select ARCH_HAS_SET_DIRECT_MAP
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_STRICT_KERNEL_RWX if MMU
+	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
+	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT

arch/riscv/include/asm/gdb_xml.h

@@ -3,8 +3,7 @@
 #ifndef __ASM_GDB_XML_H_
 #define __ASM_GDB_XML_H_
 
-#define kgdb_arch_gdb_stub_feature riscv_gdb_stub_feature
-static const char riscv_gdb_stub_feature[64] =
+const char riscv_gdb_stub_feature[64] =
 			"PacketSize=800;qXfer:features:read+;";
 
 static const char gdb_xfer_read_target[31] = "qXfer:features:read:target.xml:";

arch/riscv/include/asm/kgdb.h

@@ -19,7 +19,6 @@
 
 #ifndef	__ASSEMBLY__
 
-extern int kgdb_has_hit_break(unsigned long addr);
 extern unsigned long kgdb_compiled_break;
 
 static inline void arch_kgdb_breakpoint(void)
@@ -106,7 +105,9 @@ static inline void arch_kgdb_breakpoint(void)
 #define DBG_REG_BADADDR_OFF 34
 #define DBG_REG_CAUSE_OFF 35
 
-#include <asm/gdb_xml.h>
+extern const char riscv_gdb_stub_feature[64];
+
+#define kgdb_arch_gdb_stub_feature riscv_gdb_stub_feature
 
 #endif
 #endif

arch/riscv/kernel/kgdb.c

@@ -44,18 +44,18 @@ DECLARE_INSN(c_beqz, MATCH_C_BEQZ, MASK_C_BEQZ)
 DECLARE_INSN(c_bnez, MATCH_C_BNEZ, MASK_C_BNEZ)
 DECLARE_INSN(sret, MATCH_SRET, MASK_SRET)
 
-int decode_register_index(unsigned long opcode, int offset)
+static int decode_register_index(unsigned long opcode, int offset)
 {
 	return (opcode >> offset) & 0x1F;
 }
 
-int decode_register_index_short(unsigned long opcode, int offset)
+static int decode_register_index_short(unsigned long opcode, int offset)
 {
 	return ((opcode >> offset) & 0x7) + 8;
 }
 
 /* Calculate the new address for after a step */
-int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
+static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
 {
 	unsigned long pc = regs->epc;
 	unsigned long *regs_ptr = (unsigned long *)regs;
@@ -136,7 +136,7 @@ int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
 	return 0;
 }
 
-int do_single_step(struct pt_regs *regs)
+static int do_single_step(struct pt_regs *regs)
 {
 	/* Determine where the target instruction will send us to */
 	unsigned long addr = 0;
@@ -320,7 +320,7 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 	return err;
 }
 
-int kgdb_riscv_kgdbbreak(unsigned long addr)
+static int kgdb_riscv_kgdbbreak(unsigned long addr)
 {
 	if (stepped_address == addr)
 		return KGDB_SW_SINGLE_STEP;

include/linux/kgdb.h

@@ -176,6 +176,17 @@ kgdb_arch_handle_exception(int vector, int signo, int err_code,
 			   char *remcom_out_buffer,
 			   struct pt_regs *regs);
 
+/**
+ *	kgdb_arch_handle_qxfer_pkt - Handle architecture specific GDB XML
+ *				     packets.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ */
+
+extern void
+kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
+			   char *remcom_out_buffer);
+
 /**
  *	kgdb_call_nmi_hook - Call kgdb_nmicallback() on the current CPU
  *	@ignored: This parameter is only here to match the prototype.
@@ -314,6 +325,7 @@ extern int kgdb_hex2mem(char *buf, char *mem, int count);
 
 extern int kgdb_isremovedbreak(unsigned long addr);
 extern void kgdb_schedule_breakpoint(void);
+extern int kgdb_has_hit_break(unsigned long addr);
 
 extern int
 kgdb_handle_exception(int ex_vector, int signo, int err_code,

kernel/debug/gdbstub.c

@@ -792,6 +792,19 @@ static void gdb_cmd_query(struct kgdb_state *ks)
 		}
 		break;
 #endif
+#ifdef CONFIG_HAVE_ARCH_KGDB_QXFER_PKT
+	case 'S':
+		if (!strncmp(remcom_in_buffer, "qSupported:", 11))
+			strcpy(remcom_out_buffer, kgdb_arch_gdb_stub_feature);
+		break;
+	case 'X':
+		if (!strncmp(remcom_in_buffer, "qXfer:", 6))
+			kgdb_arch_handle_qxfer_pkt(remcom_in_buffer,
+						   remcom_out_buffer);
+		break;
+#endif
+	default:
+		break;
 	}
 }
 

lib/Kconfig.kgdb

@@ -3,6 +3,11 @@
 config HAVE_ARCH_KGDB
 	bool
 
+# set if architecture has the its kgdb_arch_handle_qxfer_pkt
+# function to enable gdb stub to address XML packet sent from GDB.
+config HAVE_ARCH_KGDB_QXFER_PKT
+	bool
+
 menuconfig KGDB
 	bool "KGDB: kernel debugger"
 	depends on HAVE_ARCH_KGDB