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authorSteve Reinhardt <stever@eecs.umich.edu>2005-09-24 14:20:29 -0400
committerSteve Reinhardt <stever@eecs.umich.edu>2005-09-24 14:20:29 -0400
commitd60de7122da3a90a0204853f633d34d93dcc622f (patch)
treef924b3f340c67c752efd7648b8e1f7ce7958425d /sim
parentb15a7aaf5e2099a3d13061c63246bed8378d2e2f (diff)
downloadgem5-d60de7122da3a90a0204853f633d34d93dcc622f.tar.xz
Add functions to System object to set up function-based events,
including automatically fixing up addresses to deal with optionally executed Alpha gp update prolog. SConscript: Remove freebsd_events.cc and linux_events.cc. base/remote_gdb.cc: cpu/pc_event.cc: kern/system_events.cc: kern/system_events.hh: PCEvents now schedule themselves in constructor. cpu/pc_event.hh: PCEvents now schedule themselves in the constructor. Get rid of constructor versions that don't take an address and all the schedule() methods that are now unnecessary. kern/freebsd/freebsd_system.cc: kern/freebsd/freebsd_system.hh: Use new System methods to schedule function-based events. Move FreeBSD-specific function event classes into FreebsdSystem. kern/linux/linux_system.cc: kern/linux/linux_system.hh: Use new System methods to schedule function-based events. Move Linux-specific function event classes into LinuxSystem. kern/tru64/tru64_events.hh: PCEvents now schedule themselves in constructor. Add DebugPrintfrEvent to encapsulate raw setting as new type (to work better with new System function-event method.) kern/tru64/tru64_system.cc: Use new System methods to schedule function-based events. kern/tru64/tru64_system.hh: Add DebugPrintfrEvent to encapsulate raw setting as new type (to work better with new System function-event method.) sim/system.cc: sim/system.hh: Add functions to set up function-based events, including automatically fixing up addresses to deal with optionally executed Alpha gp update prolog. --HG-- extra : convert_revision : c2cf09144297b6602afe755a34a0a2227023783f
Diffstat (limited to 'sim')
-rw-r--r--sim/system.cc64
-rw-r--r--sim/system.hh51
2 files changed, 110 insertions, 5 deletions
diff --git a/sim/system.cc b/sim/system.cc
index 3da92c447..e67cae333 100644
--- a/sim/system.cc
+++ b/sim/system.cc
@@ -124,9 +124,7 @@ System::System(Params *p)
Addr addr = 0;
#ifdef DEBUG
- consolePanicEvent = new BreakPCEvent(&pcEventQueue, "console panic");
- if (consoleSymtab->findAddress("panic", addr))
- consolePanicEvent->schedule(addr);
+ consolePanicEvent = addConsoleFuncEvent<BreakPCEvent>("panic");
#endif
/**
@@ -180,6 +178,65 @@ System::~System()
#endif
}
+
+/**
+ * This function fixes up addresses that are used to match PCs for
+ * hooking simulator events on to target function executions.
+ *
+ * Alpha binaries may have multiple global offset table (GOT)
+ * sections. A function that uses the GOT starts with a
+ * two-instruction prolog which sets the global pointer (gp == r29) to
+ * the appropriate GOT section. The proper gp value is calculated
+ * based on the function address, which must be passed by the caller
+ * in the procedure value register (pv aka t12 == r27). This sequence
+ * looks like the following:
+ *
+ * opcode Ra Rb offset
+ * ldah gp,X(pv) 09 29 27 X
+ * lda gp,Y(gp) 08 29 29 Y
+ *
+ * for some constant offsets X and Y. The catch is that the linker
+ * (or maybe even the compiler, I'm not sure) may recognize that the
+ * caller and callee are using the same GOT section, making this
+ * prolog redundant, and modify the call target to skip these
+ * instructions. If we check for execution of the first instruction
+ * of a function (the one the symbol points to) to detect when to skip
+ * it, we'll miss all these modified calls. It might work to
+ * unconditionally check for the third instruction, but not all
+ * functions have this prolog, and there's some chance that those
+ * first two instructions could have undesired consequences. So we do
+ * the Right Thing and pattern-match the first two instructions of the
+ * function to decide where to patch.
+ *
+ * Eventually this code should be moved into an ISA-specific file.
+ */
+Addr
+System::fixFuncEventAddr(Addr addr)
+{
+ // mask for just the opcode, Ra, and Rb fields (not the offset)
+ const uint32_t inst_mask = 0xffff0000;
+ // ldah gp,X(pv): opcode 9, Ra = 29, Rb = 27
+ const uint32_t gp_ldah_pattern = (9 << 26) | (29 << 21) | (27 << 16);
+ // lda gp,Y(gp): opcode 8, Ra = 29, rb = 29
+ const uint32_t gp_lda_pattern = (8 << 26) | (29 << 21) | (29 << 16);
+ // instruction size
+ const int sz = sizeof(uint32_t);
+
+ Addr paddr = vtophys(physmem, addr);
+ uint32_t i1 = *(uint32_t *)physmem->dma_addr(paddr, sz);
+ uint32_t i2 = *(uint32_t *)physmem->dma_addr(paddr+sz, sz);
+
+ if ((i1 & inst_mask) == gp_ldah_pattern &&
+ (i2 & inst_mask) == gp_lda_pattern) {
+ Addr new_addr = addr + 2*sz;
+ DPRINTF(Loader, "fixFuncEventAddr: %p -> %p", addr, new_addr);
+ return new_addr;
+ } else {
+ return addr;
+ }
+}
+
+
void
System::setAlphaAccess(Addr access)
{
@@ -197,6 +254,7 @@ System::setAlphaAccess(Addr access)
panic("could not find m5AlphaAccess\n");
}
+
bool
System::breakpoint()
{
diff --git a/sim/system.hh b/sim/system.hh
index 870805e4c..c4ecc9458 100644
--- a/sim/system.hh
+++ b/sim/system.hh
@@ -33,6 +33,7 @@
#include <vector>
#include "base/statistics.hh"
+#include "base/loader/symtab.hh"
#include "cpu/pc_event.hh"
#include "kern/system_events.hh"
#include "sim/sim_object.hh"
@@ -45,7 +46,6 @@ class ObjectFile;
class PhysicalMemory;
class Platform;
class RemoteGDB;
-class SymbolTable;
namespace Kernel { class Binning; }
class System : public SimObject
@@ -68,7 +68,7 @@ class System : public SimObject
return numcpus;
}
- /** kernel Symbol table */
+ /** kernel symbol table */
SymbolTable *kernelSymtab;
/** console symbol table */
@@ -102,6 +102,53 @@ class System : public SimObject
BreakPCEvent *consolePanicEvent;
#endif
+ protected:
+
+ /**
+ * Fix up an address used to match PCs for hooking simulator
+ * events on to target function executions. See comment in
+ * system.cc for details.
+ */
+ Addr fixFuncEventAddr(Addr addr);
+
+ /**
+ * Add a function-based event to the given function, to be looked
+ * up in the specified symbol table.
+ */
+ template <class T>
+ T *System::addFuncEvent(SymbolTable *symtab, const char *lbl)
+ {
+ Addr addr;
+
+ if (symtab->findAddress(lbl, addr)) {
+ T *ev = new T(&pcEventQueue, lbl, fixFuncEventAddr(addr));
+ return ev;
+ }
+
+ return NULL;
+ }
+
+ /** Add a function-based event to kernel code. */
+ template <class T>
+ T *System::addKernelFuncEvent(const char *lbl)
+ {
+ return addFuncEvent<T>(kernelSymtab, lbl);
+ }
+
+ /** Add a function-based event to PALcode. */
+ template <class T>
+ T *System::addPalFuncEvent(const char *lbl)
+ {
+ return addFuncEvent<T>(palSymtab, lbl);
+ }
+
+ /** Add a function-based event to the console code. */
+ template <class T>
+ T *System::addConsoleFuncEvent(const char *lbl)
+ {
+ return addFuncEvent<T>(consoleSymtab, lbl);
+ }
+
public:
std::vector<RemoteGDB *> remoteGDB;
std::vector<GDBListener *> gdbListen;