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loader: extend memory region descriptors a touch more gracefully

This commit is contained in:
Michael Scire 2020-08-21 03:01:39 -07:00 committed by SciresM
parent 79c9bed528
commit 25ba61adae
3 changed files with 34 additions and 0 deletions

View file

@ -47,6 +47,9 @@ namespace ams::ldr::caps {
return static_cast<CapabilityId>(__builtin_ctz(~cap.value));
}
constexpr inline util::BitPack32 EmptyCapability = {~u32{}};
static_assert(GetCapabilityId(EmptyCapability) == CapabilityId::Empty);
#define CAPABILITY_CLASS_NAME(id) Capability##id
#define DEFINE_CAPABILITY_CLASS(id, member_functions) \
@ -407,4 +410,28 @@ namespace ams::ldr::caps {
}
}
void ProcessCapabilities(void *kac, size_t kac_size) {
util::BitPack32 *caps = reinterpret_cast<util::BitPack32 *>(kac);
const size_t num_caps = kac_size / sizeof(*caps);
for (size_t i = 0; i < num_caps; i++) {
const auto cur_cap = caps[i];
switch (GetCapabilityId(cur_cap)) {
case CapabilityId::MapRegion:
{
/* MapRegion was added in 8.0.0+. */
/* To prevent kernel error, we should reject the descriptor on lower firmwares. */
/* NOTE: We also allow it on any firmware under mesosphere, as an extension. */
const bool is_allowed = (hos::GetVersion() >= hos::Version_8_0_0 || svc::IsKernelMesosphere());
if (!is_allowed) {
caps[i] = EmptyCapability;
}
}
break;
default:
break;
}
}
}
}

View file

@ -23,4 +23,6 @@ namespace ams::ldr::caps {
u16 GetProgramInfoFlags(const void *kac, size_t kac_size);
void SetProgramInfoFlags(u16 flags, void *kac, size_t kac_size);
void ProcessCapabilities(void *kac, size_t kac_size);
}

View file

@ -225,6 +225,11 @@ namespace ams::ldr {
}
}
/* Pre-process the capabilities. */
/* This is used to e.g. avoid passing memory region descriptor to older kernels. */
caps::ProcessCapabilities(meta->acid_kac, meta->acid->kac_size);
caps::ProcessCapabilities(meta->aci_kac, meta->aci->kac_size);
/* Set output. */
g_cached_program_id = loc.program_id;
g_cached_override_status = status;