tile: provide traceability for hypervisor calls

This change adds infrastructure (CONFIG_TILE_HVGLUE_TRACE) that
provides C code wrappers for the calls the kernel makes to the Tilera
hypervisor.  This allows standard kernel infrastructure like FTRACE to
be able to instrument hypervisor calls.

To allow direct calls to the true API, we export their names with a
leading underscore as well.  This is important for the few contexts
where we need to make hypervisor calls without touching the stack.

As part of this change, we also switch from creating the symbols
with linker magic to creating them with assembler magic.  This lets
us provide a symbol type and generally make them appear more as symbols
and less as just random values in the Elf namespace.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/Kconfig.debug

@@ -24,4 +24,12 @@ config DEBUG_EXTRA_FLAGS
 	  size and build time noticeably.  Such flags are often
 	  helpful if the main use of debug info is line number info.
 
+config TILE_HVGLUE_TRACE
+	bool "Provide wrapper functions for hypervisor ABI calls"
+	default n
+	help
+	  Provide wrapper functions for the hypervisor ABI calls
+	  defined in arch/tile/kernel/hvglue.S.  This allows tracing
+	  mechanisms, etc., to have visibility into those calls.
+
 endmenu

arch/tile/kernel/Makefile

@@ -3,7 +3,7 @@
 #
 
 extra-y := vmlinux.lds head_$(BITS).o
-obj-y := backtrace.o entry.o irq.o messaging.o \
+obj-y := backtrace.o entry.o hvglue.o irq.o messaging.o \
 	pci-dma.o proc.o process.o ptrace.o reboot.o \
 	setup.o signal.o single_step.o stack.o sys.o \
 	sysfs.o time.o traps.o unaligned.o vdso.o \
@@ -21,5 +21,6 @@ else
 obj-$(CONFIG_PCI)		+= pci.o
 endif
 obj-$(CONFIG_TILE_USB)		+= usb.o
+obj-$(CONFIG_TILE_HVGLUE_TRACE)	+= hvglue_trace.o
 
 obj-y				+= vdso/

arch/tile/kernel/head_32.S

@@ -39,12 +39,12 @@ ENTRY(_start)
 	}
 	{
 	  moveli r0, _HV_VERSION_OLD_HV_INIT
-	  jal hv_init
+	  jal _hv_init
 	}
 	/* Get a reasonable default ASID in r0 */
 	{
 	  move r0, zero
-	  jal hv_inquire_asid
+	  jal _hv_inquire_asid
 	}
 	/* Install the default page table */
 	{
@@ -73,12 +73,12 @@ ENTRY(_start)
 	}
 	{
 	  auli lr, lr, ha16(1f)
-	  j hv_install_context
+	  j _hv_install_context
 	}
 1:
 
 	/* Get our processor number and save it away in SAVE_K_0. */
-	jal hv_inquire_topology
+	jal _hv_inquire_topology
 	mulll_uu r4, r1, r2        /* r1 == y, r2 == width */
 	add r4, r4, r0             /* r0 == x, so r4 == cpu == y*width + x */
 

arch/tile/kernel/head_64.S

@@ -55,11 +55,11 @@ ENTRY(_start)
 	  movei r2, TILE_CHIP_REV
 	  movei r3, KERNEL_PL
 	}
-	jal hv_init
+	jal _hv_init
 	/* Get a reasonable default ASID in r0 */
 	{
 	  move r0, zero
-	  jal hv_inquire_asid
+	  jal _hv_inquire_asid
 	}
 
 	/*
@@ -130,7 +130,7 @@ ENTRY(_start)
 	}
 	{
 	  moveli r3, CTX_PAGE_FLAG
-	  j hv_install_context
+	  j _hv_install_context
 	}
 1:
 
@@ -141,7 +141,7 @@ ENTRY(_start)
 	mtspr SPR_INTERRUPT_VECTOR_BASE_K, r0
 
 	/* Get our processor number and save it away in SAVE_K_0. */
-	jal hv_inquire_topology
+	jal _hv_inquire_topology
 	{
 	  GET_FIRST_INT(r5, r1)   /* r5 = width */
 	  GET_SECOND_INT(r4, r0)  /* r4 = y */

arch/tile/kernel/hvglue.S

+/* Hypervisor call vector addresses; see <hv/hypervisor.h> */
+.macro gensym sym, val, size
+.org \val
+.global _\sym
+.type _\sym,function
+_\sym:
+.size _\sym,\size
+#ifndef CONFIG_TILE_HVGLUE_TRACE
+.globl \sym
+.set \sym,_\sym
+#endif
+.endm
+
+.section .hvglue,"x",@nobits
+.align 8
+gensym hv_init, 0x20, 32
+gensym hv_install_context, 0x40, 32
+gensym hv_sysconf, 0x60, 32
+gensym hv_get_rtc, 0x80, 32
+gensym hv_set_rtc, 0xa0, 32
+gensym hv_flush_asid, 0xc0, 32
+gensym hv_flush_page, 0xe0, 32
+gensym hv_flush_pages, 0x100, 32
+gensym hv_restart, 0x120, 32
+gensym hv_halt, 0x140, 32
+gensym hv_power_off, 0x160, 32
+gensym hv_inquire_physical, 0x180, 32
+gensym hv_inquire_memory_controller, 0x1a0, 32
+gensym hv_inquire_virtual, 0x1c0, 32
+gensym hv_inquire_asid, 0x1e0, 32
+gensym hv_nanosleep, 0x200, 32
+gensym hv_console_read_if_ready, 0x220, 32
+gensym hv_console_write, 0x240, 32
+gensym hv_downcall_dispatch, 0x260, 32
+gensym hv_inquire_topology, 0x280, 32
+gensym hv_fs_findfile, 0x2a0, 32
+gensym hv_fs_fstat, 0x2c0, 32
+gensym hv_fs_pread, 0x2e0, 32
+gensym hv_physaddr_read64, 0x300, 32
+gensym hv_physaddr_write64, 0x320, 32
+gensym hv_get_command_line, 0x340, 32
+gensym hv_set_caching, 0x360, 32
+gensym hv_bzero_page, 0x380, 32
+gensym hv_register_message_state, 0x3a0, 32
+gensym hv_send_message, 0x3c0, 32
+gensym hv_receive_message, 0x3e0, 32
+gensym hv_inquire_context, 0x400, 32
+gensym hv_start_all_tiles, 0x420, 32
+gensym hv_dev_open, 0x440, 32
+gensym hv_dev_close, 0x460, 32
+gensym hv_dev_pread, 0x480, 32
+gensym hv_dev_pwrite, 0x4a0, 32
+gensym hv_dev_poll, 0x4c0, 32
+gensym hv_dev_poll_cancel, 0x4e0, 32
+gensym hv_dev_preada, 0x500, 32
+gensym hv_dev_pwritea, 0x520, 32
+gensym hv_flush_remote, 0x540, 32
+gensym hv_console_putc, 0x560, 32
+gensym hv_inquire_tiles, 0x580, 32
+gensym hv_confstr, 0x5a0, 32
+gensym hv_reexec, 0x5c0, 32
+gensym hv_set_command_line, 0x5e0, 32
+gensym hv_clear_intr, 0x600, 32
+gensym hv_enable_intr, 0x620, 32
+gensym hv_disable_intr, 0x640, 32
+gensym hv_raise_intr, 0x660, 32
+gensym hv_trigger_ipi, 0x680, 32
+gensym hv_store_mapping, 0x6a0, 32
+gensym hv_inquire_realpa, 0x6c0, 32
+gensym hv_flush_all, 0x6e0, 32
+gensym hv_get_ipi_pte, 0x700, 32
+gensym hv_set_pte_super_shift, 0x720, 32
+gensym hv_console_set_ipi, 0x7e0, 32
+gensym hv_glue_internals, 0x800, 30720

arch/tile/kernel/hvglue.lds

-/* Hypervisor call vector addresses; see <hv/hypervisor.h> */
-hv_init = TEXT_OFFSET + 0x10020;
-hv_install_context = TEXT_OFFSET + 0x10040;
-hv_sysconf = TEXT_OFFSET + 0x10060;
-hv_get_rtc = TEXT_OFFSET + 0x10080;
-hv_set_rtc = TEXT_OFFSET + 0x100a0;
-hv_flush_asid = TEXT_OFFSET + 0x100c0;
-hv_flush_page = TEXT_OFFSET + 0x100e0;
-hv_flush_pages = TEXT_OFFSET + 0x10100;
-hv_restart = TEXT_OFFSET + 0x10120;
-hv_halt = TEXT_OFFSET + 0x10140;
-hv_power_off = TEXT_OFFSET + 0x10160;
-hv_inquire_physical = TEXT_OFFSET + 0x10180;
-hv_inquire_memory_controller = TEXT_OFFSET + 0x101a0;
-hv_inquire_virtual = TEXT_OFFSET + 0x101c0;
-hv_inquire_asid = TEXT_OFFSET + 0x101e0;
-hv_nanosleep = TEXT_OFFSET + 0x10200;
-hv_console_read_if_ready = TEXT_OFFSET + 0x10220;
-hv_console_write = TEXT_OFFSET + 0x10240;
-hv_downcall_dispatch = TEXT_OFFSET + 0x10260;
-hv_inquire_topology = TEXT_OFFSET + 0x10280;
-hv_fs_findfile = TEXT_OFFSET + 0x102a0;
-hv_fs_fstat = TEXT_OFFSET + 0x102c0;
-hv_fs_pread = TEXT_OFFSET + 0x102e0;
-hv_physaddr_read64 = TEXT_OFFSET + 0x10300;
-hv_physaddr_write64 = TEXT_OFFSET + 0x10320;
-hv_get_command_line = TEXT_OFFSET + 0x10340;
-hv_set_caching = TEXT_OFFSET + 0x10360;
-hv_bzero_page = TEXT_OFFSET + 0x10380;
-hv_register_message_state = TEXT_OFFSET + 0x103a0;
-hv_send_message = TEXT_OFFSET + 0x103c0;
-hv_receive_message = TEXT_OFFSET + 0x103e0;
-hv_inquire_context = TEXT_OFFSET + 0x10400;
-hv_start_all_tiles = TEXT_OFFSET + 0x10420;
-hv_dev_open = TEXT_OFFSET + 0x10440;
-hv_dev_close = TEXT_OFFSET + 0x10460;
-hv_dev_pread = TEXT_OFFSET + 0x10480;
-hv_dev_pwrite = TEXT_OFFSET + 0x104a0;
-hv_dev_poll = TEXT_OFFSET + 0x104c0;
-hv_dev_poll_cancel = TEXT_OFFSET + 0x104e0;
-hv_dev_preada = TEXT_OFFSET + 0x10500;
-hv_dev_pwritea = TEXT_OFFSET + 0x10520;
-hv_flush_remote = TEXT_OFFSET + 0x10540;
-hv_console_putc = TEXT_OFFSET + 0x10560;
-hv_inquire_tiles = TEXT_OFFSET + 0x10580;
-hv_confstr = TEXT_OFFSET + 0x105a0;
-hv_reexec = TEXT_OFFSET + 0x105c0;
-hv_set_command_line = TEXT_OFFSET + 0x105e0;
-hv_clear_intr = TEXT_OFFSET + 0x10600;
-hv_enable_intr = TEXT_OFFSET + 0x10620;
-hv_disable_intr = TEXT_OFFSET + 0x10640;
-hv_raise_intr = TEXT_OFFSET + 0x10660;
-hv_trigger_ipi = TEXT_OFFSET + 0x10680;
-hv_store_mapping = TEXT_OFFSET + 0x106a0;
-hv_inquire_realpa = TEXT_OFFSET + 0x106c0;
-hv_flush_all = TEXT_OFFSET + 0x106e0;
-hv_get_ipi_pte = TEXT_OFFSET + 0x10700;
-hv_set_pte_super_shift = TEXT_OFFSET + 0x10720;
-hv_console_set_ipi = TEXT_OFFSET + 0x107e0;
-hv_glue_internals = TEXT_OFFSET + 0x10800;

arch/tile/kernel/intvec_32.S

@@ -758,7 +758,7 @@ intvec_\vecname:
 	.macro  dc_dispatch vecnum, vecname
 	.org    (\vecnum << 8)
 intvec_\vecname:
-	j       hv_downcall_dispatch
+	j       _hv_downcall_dispatch
 	ENDPROC(intvec_\vecname)
 	.endm
 

arch/tile/kernel/intvec_64.S

@@ -772,7 +772,7 @@ intvec_\vecname:
 	.macro  dc_dispatch vecnum, vecname
 	.org    (\vecnum << 8)
 intvec_\vecname:
-	j       hv_downcall_dispatch
+	j       _hv_downcall_dispatch
 	ENDPROC(intvec_\vecname)
 	.endm
 

arch/tile/kernel/vmlinux.lds.S

@@ -31,7 +31,10 @@ SECTIONS
   } :intrpt1 =0
 
   /* Hypervisor call vectors */
-  #include "hvglue.lds"
+  . = ALIGN(0x10000);
+  .hvglue : AT (ADDR(.hvglue) - LOAD_OFFSET) {
+    *(.hvglue)
+  } :NONE
 
   /* Now the real code */
   . = ALIGN(0x20000);

arch/tile/mm/migrate_32.S

@@ -136,7 +136,7 @@ STD_ENTRY(flush_and_install_context)
 	 move r8, zero  /* asids */
 	 move r9, zero  /* asidcount */
 	}
-	jal hv_flush_remote
+	jal _hv_flush_remote
 	bnz r0, .Ldone
 
 	/* Now install the new page table. */
@@ -152,7 +152,7 @@ STD_ENTRY(flush_and_install_context)
 	 move r4, r_asid
 	 moveli r5, HV_CTX_DIRECTIO | CTX_PAGE_FLAG
 	}
-	jal hv_install_context
+	jal _hv_install_context
 	bnz r0, .Ldone
 
 	/* Finally, flush the TLB. */

arch/tile/mm/migrate_64.S

@@ -123,7 +123,7 @@ STD_ENTRY(flush_and_install_context)
 	}
 	{
 	 move r8, zero  /* asidcount */
-	 jal hv_flush_remote
+	 jal _hv_flush_remote
 	}
 	bnez r0, 1f
 
@@ -136,7 +136,7 @@ STD_ENTRY(flush_and_install_context)
 	 move r2, r_asid
 	 moveli r3, HV_CTX_DIRECTIO | CTX_PAGE_FLAG
 	}
-	jal hv_install_context
+	jal _hv_install_context
 	bnez r0, 1f
 
 	/* Finally, flush the TLB. */