minidump: Parameterize minidumpsys()

The minidump code is written assuming that certain global state will not
change, and rightly so, since it executes from a kernel debugger
context. In order to support taking minidumps of a live system, we
should allow copies of relevant global state that is likely to change to
be passed as parameters to the minidumpsys() function.

This patch does the work of parameterizing this function, by adding a
struct minidumpstate argument. For now, this struct allows for copies of
the kernel message buffer, and the bitset that tracks which pages should
be dumped (vm_page_dump). Follow-up changes will actually make use of
these arguments.

Notably, dump_avail[] does not need a snapshot, since it is not expected
to change after system initialization.

The existing minidumpsys() definitions are renamed, and a thin MI
wrapper is added to kern_dump.c, which handles the construction of
the state struct. Thus, calling minidumpsys() remains as simple as
before.

Reviewed by:	kib, markj, jhb
Sponsored by:	Juniper Networks, Inc.
Sponsored by:	Klara, Inc.
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D31989

sys/amd64/amd64/minidump_machdep.c

@@ -160,7 +160,7 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 static pd_entry_t fakepd[NPDEPG];
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 	uint32_t pmapsize;
 	vm_offset_t va;

sys/arm/arm/minidump_machdep.c

@@ -153,7 +153,7 @@ static char dumpbuf[PAGE_SIZE] __aligned(sizeof(uint64_t));
 CTASSERT(sizeof(dumpbuf) % sizeof(pt2_entry_t) == 0);
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 	struct minidumphdr mdhdr;
 	uint64_t dumpsize, *dump_avail_buf;

sys/arm/include/md_var.h

@@ -52,9 +52,10 @@ enum cpu_class {
 extern enum cpu_class cpu_class;
 
 struct dumperinfo;
+struct minidumpstate;
 extern int busdma_swi_pending;
 void busdma_swi(void);
-int minidumpsys(struct dumperinfo *);
+int cpu_minidumpsys(struct dumperinfo *, const struct minidumpstate *);
 
 extern uint32_t initial_fpscr;
 

sys/arm64/arm64/minidump_machdep.c

@@ -147,7 +147,7 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 }
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 	struct minidumphdr mdhdr;
 	pd_entry_t *l0, *l1, *l2;

sys/arm64/include/md_var.h

@@ -44,10 +44,11 @@ extern u_long elf32_hwcap2;
 #endif
 
 struct dumperinfo;
+struct minidumpstate;
 
 extern int busdma_swi_pending;
 void busdma_swi(void);
-int minidumpsys(struct dumperinfo *);
+int cpu_minidumpsys(struct dumperinfo *, const struct minidumpstate *);
 void generic_bs_fault(void) __asm(__STRING(generic_bs_fault));
 void generic_bs_peek_1(void) __asm(__STRING(generic_bs_peek_1));
 void generic_bs_peek_2(void) __asm(__STRING(generic_bs_peek_2));

sys/i386/i386/minidump_machdep.c

@@ -50,8 +50,9 @@ __FBSDID("$FreeBSD$");
 CTASSERT(sizeof(struct kerneldumpheader) == 512);
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 
-	return (pae_mode ? minidumpsys_pae(di) : minidumpsys_nopae(di));
+	return (pae_mode ? cpu_minidumpsys_pae(di, state) :
+	    cpu_minidumpsys_nopae(di, state));
 }

sys/i386/i386/minidump_machdep_base.c

@@ -145,15 +145,15 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 static pt_entry_t fakept[NPTEPG];
 
 #ifdef PMAP_PAE_COMP
-#define	minidumpsys	minidumpsys_pae
-#define	IdlePTD		IdlePTD_pae
+#define	cpu_minidumpsys		cpu_minidumpsys_pae
+#define	IdlePTD			IdlePTD_pae
 #else
-#define	minidumpsys	minidumpsys_nopae
-#define	IdlePTD		IdlePTD_nopae
+#define	cpu_minidumpsys		cpu_minidumpsys_nopae
+#define	IdlePTD			IdlePTD_nopae
 #endif
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 	uint64_t dumpsize;
 	uint32_t ptesize;

sys/i386/include/md_var.h

@@ -68,8 +68,8 @@ void	doreti_popl_fs_fault(void) __asm(__STRING(doreti_popl_fs_fault));
 void	fill_based_sd(struct segment_descriptor *sdp, uint32_t base);
 void	i686_pagezero(void *addr);
 void	sse2_pagezero(void *addr);
-int	minidumpsys_nopae(struct dumperinfo *);
-int	minidumpsys_pae(struct dumperinfo *);
+int	cpu_minidumpsys_nopae(struct dumperinfo *, const struct minidumpstate *);
+int	cpu_minidumpsys_pae(struct dumperinfo *, const struct minidumpstate *);
 void	init_AMD_Elan_sc520(void);
 vm_paddr_t kvtop(void *addr);
 void	panicifcpuunsupported(void);

sys/kern/kern_dump.c

@@ -32,15 +32,18 @@ __FBSDID("$FreeBSD$");
 #include <sys/conf.h>
 #include <sys/cons.h>
 #include <sys/kernel.h>
-#include <sys/proc.h>
 #include <sys/kerneldump.h>
+#include <sys/msgbuf.h>
+#include <sys/proc.h>
 #include <sys/watchdog.h>
+
 #include <vm/vm.h>
 #include <vm/vm_param.h>
 #include <vm/vm_page.h>
 #include <vm/vm_phys.h>
 #include <vm/vm_dumpset.h>
 #include <vm/pmap.h>
+
 #include <machine/dump.h>
 #include <machine/elf.h>
 #include <machine/md_var.h>
@@ -386,6 +389,8 @@ dumpsys_generic(struct dumperinfo *di)
 	return (error);
 }
 
+#if MINIDUMP_PAGE_TRACKING == 1
+
 /* Minidump progress bar */
 static struct {
 	const int min_per;
@@ -454,3 +459,18 @@ dumpsys_pb_progress(size_t delta)
 		break;
 	}
 }
+
+int
+minidumpsys(struct dumperinfo *di)
+{
+	struct minidumpstate state;
+	int error;
+
+	state.msgbufp = msgbufp;
+	state.dump_bitset = vm_page_dump;
+
+	error = cpu_minidumpsys(di, &state);
+
+	return (error);
+}
+#endif /* MINIDUMP_PAGE_TRACKING == 1 */

sys/mips/include/md_var.h

@@ -82,6 +82,7 @@ extern int busdma_swi_pending;
 void	busdma_swi(void);
 
 struct	dumperinfo;
-int	minidumpsys(struct dumperinfo *);
+struct	minidumpstate;
+int	cpu_minidumpsys(struct dumperinfo *, const struct minidumpstate *);
 
 #endif /* !_MACHINE_MD_VAR_H_ */

sys/mips/mips/minidump_machdep.c

@@ -106,7 +106,7 @@ write_buffer(struct dumperinfo *di, char *ptr, size_t sz)
 }
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 	struct minidumphdr mdhdr;
 	uint64_t *dump_avail_buf;

sys/powerpc/include/md_var.h

@@ -43,7 +43,8 @@ extern	char	sigcode64[], sigcode64_elfv2[];
 extern	int	szsigcode64, szsigcode64_elfv2;
 
 struct	dumperinfo;
-int	minidumpsys(struct dumperinfo *);
+struct	minidumpstate;
+int	cpu_minidumpsys(struct dumperinfo *, const struct minidumpstate *);
 #endif
 
 extern	long	Maxmem;

sys/powerpc/powerpc/minidump_machdep.c

@@ -189,7 +189,7 @@ dump_pmap(struct dumperinfo *di)
 }
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 	vm_paddr_t pa;
 	int error, retry_count;

sys/riscv/include/md_var.h

@@ -42,8 +42,9 @@ extern register_t marchid;
 extern register_t mimpid;
 
 struct dumperinfo;
+struct minidumpstate;
 
 void busdma_swi(void);
-int minidumpsys(struct dumperinfo *);
+int cpu_minidumpsys(struct dumperinfo *, const struct minidumpstate *);
 
 #endif /* !_MACHINE_MD_VAR_H_ */

sys/riscv/riscv/minidump_machdep.c

@@ -153,7 +153,7 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 }
 
 int
-minidumpsys(struct dumperinfo *di)
+cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 {
 	pd_entry_t *l1, *l2;
 	pt_entry_t *l3;

sys/sys/kerneldump.h

@@ -135,6 +135,12 @@ struct dump_pa {
 	vm_paddr_t pa_size;
 };
 
+struct minidumpstate {
+	struct msgbuf	*msgbufp;
+	struct bitset	*dump_bitset;
+};
+
+int minidumpsys(struct dumperinfo *);
 int dumpsys_generic(struct dumperinfo *);
 
 void dumpsys_map_chunk(vm_paddr_t, size_t, void **);

sys/x86/include/x86_var.h

@@ -104,6 +104,7 @@ struct	fpreg;
 struct  dbreg;
 struct	dumperinfo;
 struct	trapframe;
+struct	minidumpstate;
 
 /*
  * The interface type of the interrupt handler entry point cannot be
@@ -151,7 +152,7 @@ void	pagecopy(void *from, void *to);
 void	printcpuinfo(void);
 int	pti_get_default(void);
 int	user_dbreg_trap(register_t dr6);
-int	minidumpsys(struct dumperinfo *);
+int	cpu_minidumpsys(struct dumperinfo *, const struct minidumpstate *);
 struct pcb *get_pcb_td(struct thread *td);
 void	x86_set_fork_retval(struct thread *td);
 uint64_t rdtsc_ordered(void);