From: Alex Bennée <alex.ben...@linaro.org> The commit b3aa2f2128 (target/arm: provide stubs for more external debug registers) was added to handle HyperV's unconditional usage of Debug Communications Channel. It turns out that Linux will similarly break if you enable CONFIG_HVC_DCC "ARM JTAG DCC console".
Extend the registers we RAZ/WI set to avoid this. Cc: Anders Roxell <anders.rox...@linaro.org> Cc: Evgeny Iakovlev <eiakov...@linux.microsoft.com> Signed-off-by: Alex Bennée <alex.ben...@linaro.org> Reviewed-by: Richard Henderson <richard.hender...@linaro.org> Message-id: 20230516104420.407912-1-alex.ben...@linaro.org Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> --- target/arm/debug_helper.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/target/arm/debug_helper.c b/target/arm/debug_helper.c index dfc8b2a1a5d..d41cc643b1b 100644 --- a/target/arm/debug_helper.c +++ b/target/arm/debug_helper.c @@ -949,8 +949,10 @@ static const ARMCPRegInfo debug_cp_reginfo[] = { .access = PL0_R, .accessfn = access_tdcc, .type = ARM_CP_CONST, .resetvalue = 0 }, /* - * OSDTRRX_EL1/OSDTRTX_EL1 are used for save and restore of DBGDTRRX_EL0. - * It is a component of the Debug Communications Channel, which is not implemented. + * These registers belong to the Debug Communications Channel, + * which is not implemented. However we implement RAZ/WI behaviour + * with trapping to prevent spurious SIGILLs if the guest OS does + * access them as the support cannot be probed for. */ { .name = "OSDTRRX_EL1", .state = ARM_CP_STATE_BOTH, .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 0, .opc2 = 2, @@ -960,6 +962,11 @@ static const ARMCPRegInfo debug_cp_reginfo[] = { .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 3, .opc2 = 2, .access = PL1_RW, .accessfn = access_tdcc, .type = ARM_CP_CONST, .resetvalue = 0 }, + /* DBGDTRTX_EL0/DBGDTRRX_EL0 depend on direction */ + { .name = "DBGDTR_EL0", .state = ARM_CP_STATE_BOTH, .cp = 14, + .opc0 = 2, .opc1 = 3, .crn = 0, .crm = 5, .opc2 = 0, + .access = PL0_RW, .accessfn = access_tdcc, + .type = ARM_CP_CONST, .resetvalue = 0 }, /* * OSECCR_EL1 provides a mechanism for an operating system * to access the contents of EDECCR. EDECCR is not implemented though, -- 2.34.1