From ed399ade3c85adf82fe507339560693e83a27020 Mon Sep 17 00:00:00 2001 From: Benjamin Gray Date: Wed, 20 Mar 2024 12:50:25 +1100 Subject: [PATCH] target/ppc: Fix GDB register indexing on secondary CPUs The GDB server protocol assigns an arbitrary numbering of the SPRs. We track this correspondence on each SPR with gdb_id, using it to resolve any SPR requests GDB makes. Early on we generate an XML representation of the SPRs to give GDB, including this numbering. However the XML is cached globally, and we skip setting the SPR gdb_id values on subsequent threads if we detect it is cached. This causes QEMU to fail to resolve SPR requests against secondary CPUs because it cannot find the matching gdb_id value on that thread's SPRs. This is a minimal fix to first assign the gdb_id values, then return early if the XML is cached. Otherwise we generate the XML using the now already initialised gdb_id values. Fixes: 1b53948ff8f7 ("target/ppc: Use GDBFeature for dynamic XML") Reviewed-by: Nicholas Piggin Signed-off-by: Benjamin Gray Signed-off-by: Nicholas Piggin --- target/ppc/gdbstub.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/target/ppc/gdbstub.c b/target/ppc/gdbstub.c index 3f1e61bdb7..3b28d4e21c 100644 --- a/target/ppc/gdbstub.c +++ b/target/ppc/gdbstub.c @@ -305,6 +305,25 @@ static void gdb_gen_spr_feature(CPUState *cs) unsigned int num_regs = 0; int i; + for (i = 0; i < ARRAY_SIZE(env->spr_cb); i++) { + ppc_spr_t *spr = &env->spr_cb[i]; + + if (!spr->name) { + continue; + } + + /* + * GDB identifies registers based on the order they are + * presented in the XML. These ids will not match QEMU's + * representation (which follows the PowerISA). + * + * Store the position of the current register description so + * we can make the correspondence later. + */ + spr->gdb_id = num_regs; + num_regs++; + } + if (pcc->gdb_spr.xml) { return; } @@ -321,18 +340,8 @@ static void gdb_gen_spr_feature(CPUState *cs) } gdb_feature_builder_append_reg(&builder, g_ascii_strdown(spr->name, -1), - TARGET_LONG_BITS, num_regs, + TARGET_LONG_BITS, spr->gdb_id, "int", "spr"); - /* - * GDB identifies registers based on the order they are - * presented in the XML. These ids will not match QEMU's - * representation (which follows the PowerISA). - * - * Store the position of the current register description so - * we can make the correspondence later. - */ - spr->gdb_id = num_regs; - num_regs++; } gdb_feature_builder_end(&builder);