[Xen-devel] [PATCH v10 04/20] amd64: introduce hook for custom preload metadata parsers

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

---
 sys/amd64/amd64/machdep.c   |   41 ++++++++++++++++------
 sys/amd64/include/sysarch.h |   12 ++++++
 sys/x86/xen/pv.c            |   82 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 124 insertions(+), 11 deletions(-)

diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index f0d4ea8..343f9b8 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -126,6 +126,7 @@ __FBSDID("$FreeBSD$");
 #include <machine/reg.h>
 #include <machine/sigframe.h>
 #include <machine/specialreg.h>
+#include <machine/sysarch.h>
 #ifdef PERFMON
 #include <machine/perfmon.h>
 #endif
@@ -165,6 +166,14 @@ static int  set_fpcontext(struct thread *td, const 
mcontext_t *mcp,
     char *xfpustate, size_t xfpustate_len);
 SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL);
 
+/* Preload data parse function */
+static caddr_t native_parse_preload_data(u_int64_t);
+
+/* Default init_ops implementation. */
+struct init_ops init_ops = {
+       .parse_preload_data =   native_parse_preload_data,
+};
+
 /*
  * The file "conf/ldscript.amd64" defines the symbol "kernphys".  Its value is
  * the physical address at which the kernel is loaded.
@@ -1685,6 +1694,26 @@ do_next:
        msgbufp = (struct msgbuf *)PHYS_TO_DMAP(phys_avail[pa_indx]);
 }
 
+static caddr_t
+native_parse_preload_data(u_int64_t modulep)
+{
+       caddr_t kmdp;
+
+       preload_metadata = (caddr_t)(uintptr_t)(modulep + KERNBASE);
+       preload_bootstrap_relocate(KERNBASE);
+       kmdp = preload_search_by_type("elf kernel");
+       if (kmdp == NULL)
+               kmdp = preload_search_by_type("elf64 kernel");
+       boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
+       kern_envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *) + KERNBASE;
+#ifdef DDB
+       ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
+       ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
+#endif
+
+       return (kmdp);
+}
+
 u_int64_t
 hammer_time(u_int64_t modulep, u_int64_t physfree)
 {
@@ -1709,17 +1738,7 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
         */
        proc_linkup0(&proc0, &thread0);
 
-       preload_metadata = (caddr_t)(uintptr_t)(modulep + KERNBASE);
-       preload_bootstrap_relocate(KERNBASE);
-       kmdp = preload_search_by_type("elf kernel");
-       if (kmdp == NULL)
-               kmdp = preload_search_by_type("elf64 kernel");
-       boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
-       kern_envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *) + KERNBASE;
-#ifdef DDB
-       ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
-       ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
-#endif
+       kmdp = init_ops.parse_preload_data(modulep);
 
        /* Init basic tunables, hz etc */
        init_param1();
diff --git a/sys/amd64/include/sysarch.h b/sys/amd64/include/sysarch.h
index cd380d4..58ac8cd 100644
--- a/sys/amd64/include/sysarch.h
+++ b/sys/amd64/include/sysarch.h
@@ -4,3 +4,15 @@
 /* $FreeBSD$ */
 
 #include <x86/sysarch.h>
+
+/*
+ * Struct containing pointers to init functions whose
+ * implementation is run time selectable.  Selection can be made,
+ * for example, based on detection of a BIOS variant or
+ * hypervisor environment.
+ */
+struct init_ops {
+       caddr_t (*parse_preload_data)(u_int64_t);
+};
+
+extern struct init_ops init_ops;
diff --git a/sys/x86/xen/pv.c b/sys/x86/xen/pv.c
index db3b7a3..908b50b 100644
--- a/sys/x86/xen/pv.c
+++ b/sys/x86/xen/pv.c
@@ -46,6 +46,8 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm_pager.h>
 #include <vm/vm_param.h>
 
+#include <machine/sysarch.h>
+
 #include <xen/xen-os.h>
 #include <xen/hypervisor.h>
 
@@ -54,6 +56,36 @@ extern u_int64_t hammer_time(u_int64_t, u_int64_t);
 /* Xen initial function */
 extern u_int64_t hammer_time_xen(start_info_t *, u_int64_t);
 
+/*--------------------------- Forward Declarations 
---------------------------*/
+static caddr_t xen_pv_parse_preload_data(u_int64_t);
+
+static void xen_pv_set_init_ops(void);
+
+/*-------------------------------- Global Data 
-------------------------------*/
+/* Xen init_ops implementation. */
+struct init_ops xen_init_ops = {
+       .parse_preload_data =   xen_pv_parse_preload_data,
+};
+
+static struct
+{
+       const char      *ev;
+       int             mask;
+} howto_names[] = {
+       {"boot_askname",        RB_ASKNAME},
+       {"boot_single",         RB_SINGLE},
+       {"boot_nosync",         RB_NOSYNC},
+       {"boot_halt",           RB_ASKNAME},
+       {"boot_serial",         RB_SERIAL},
+       {"boot_cdrom",          RB_CDROM},
+       {"boot_gdb",            RB_GDB},
+       {"boot_gdb_pause",      RB_RESERVED1},
+       {"boot_verbose",        RB_VERBOSE},
+       {"boot_multicons",      RB_MULTIPLE},
+       {NULL,  0}
+};
+
+/*-------------------------------- Xen PV init 
-------------------------------*/
 /*
  * First function called by the Xen PVH boot sequence.
  *
@@ -118,6 +150,56 @@ hammer_time_xen(start_info_t *si, u_int64_t xenstack)
        }
        load_cr3(((u_int64_t)&PT4[0]) - KERNBASE);
 
+       /* Set the hooks for early functions that diverge from bare metal */
+       xen_pv_set_init_ops();
+
        /* Now we can jump into the native init function */
        return (hammer_time(0, physfree));
 }
+
+/*-------------------------------- PV specific 
-------------------------------*/
+/*
+ * Functions to convert the "extra" parameters passed by Xen
+ * into FreeBSD boot options (from the i386 Xen port).
+ */
+static char *
+xen_setbootenv(char *cmd_line)
+{
+       char *cmd_line_next;
+
+        /* Skip leading spaces */
+        for (; *cmd_line == ' '; cmd_line++);
+
+       for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;);
+       return (cmd_line);
+}
+
+static int
+xen_boothowto(char *envp)
+{
+       int i, howto = 0;
+
+       /* get equivalents from the environment */
+       for (i = 0; howto_names[i].ev != NULL; i++)
+               if (getenv(howto_names[i].ev) != NULL)
+                       howto |= howto_names[i].mask;
+       return (howto);
+}
+
+static caddr_t
+xen_pv_parse_preload_data(u_int64_t modulep)
+{
+       /* Parse the extra boot information given by Xen */
+       if (HYPERVISOR_start_info->cmd_line)
+               kern_envp = xen_setbootenv(HYPERVISOR_start_info->cmd_line);
+       boothowto |= xen_boothowto(kern_envp);
+
+       return (NULL);
+}
+
+static void
+xen_pv_set_init_ops(void)
+{
+       /* Init ops for Xen PV */
+       init_ops = xen_init_ops;
+}
-- 
1.7.7.5 (Apple Git-26)


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